Tuesday, July 27, 2010
Monday, July 19, 2010
Thanks Everyone!
Thank you very much for dropping by and commenting, everyone. I submitted my article to the Teaching and Learning Phantasmagoria yesterday but not in time to incorporate all your comments- however there will be the opportunity to incorporate more changes to the final draft. I will post successive drafts here for you, feel free to comment on them.;)
Time to Google some dodgy methods for textual analysis...
Time to Google some dodgy methods for textual analysis...
Tuesday, July 13, 2010
Just looking for some sort of feedback here...
Greetings everyone... I am hoping some of you will have a go before Monday at making some comments here. Maybe I should try offering a little structure...
* Was this course any good, or should I do something else?
* Even if it was halfway decent, what should I do to improve it?
* What advice would you give to students contemplating Honours in Chemistry about the Polymer Coursework mini-unit?
* Did you learn anything that has actually been useful to you in the time since?
* I would be keen to have specific feedback about specific exam questions if you have any memories adhering strongly from exam time.
* Was this course any good, or should I do something else?
* Even if it was halfway decent, what should I do to improve it?
* What advice would you give to students contemplating Honours in Chemistry about the Polymer Coursework mini-unit?
* Did you learn anything that has actually been useful to you in the time since?
* I would be keen to have specific feedback about specific exam questions if you have any memories adhering strongly from exam time.
Wednesday, July 7, 2010
2006 Exam
Honours Exam 2006: Control of Radical Polymerisation
Time allowed: 24 hours from receipt of exam
Resources allowed: All, but you must cite all resources used in your answers.
Answer all questions.
1. (a) How do the properties of star polymers differ from linear polymers of the same molecular weight? Why? What applications does this make star polymers particularly suitable for? (b) Outline two schemes for producing star polymers of poly(butyl acrylate): one by a ‘core first’ approach and one by an ‘arm first’ approach.
2. “In the paper by Koumura et al. (Macromolecules 39, 12, 4060), Scheme 3 illustrates a process which is likely to be important in the stereoselective polymerisation of vinyl acetate in fluoroalcohol solvents.” Do you agree with this statement? Explain what Koumura et al. are trying to tell us in Scheme 3 and explain why you agree/disagree.
3. A company offers you a large sum of money to produce an electroactive actuator from poly(vinyl acetate). Either (i) explain how you would go about designing such an actuator for them or (ii) explain to them why they should not pursue such an idea.
4. Such, Evans, and Davis (Macromolecules 39, 4, 1391-1396) fit the decolouration of photochromic dyes in a polymer matrix to a biexponential distribution, A(t) = A1e–k1t + A2e–k2t + A∞. From their Table 2, what can you say about the variation in the five fitting parameters in this distribution with the physical properties of the polymer matrix? Do you think there are any good theoretical reasons for fitting the curves to a biexponential rather than a single exponential? Outline any reasons you think of and explain how they are consistent/inconsistent with the experimental data.
5. Fava et al. (Macromolecules 39, 5, 1665-1669) prepared core-shell polymer particles by surfactant-free emulsion polymerisation. Describe this process and what they did. They state that they lightly crosslinked both the core and shell of their particles: does this cast doubt on any of their conclusions? Explain.
6. Tables 1-4 of Osawa et al.’s work on molecularly-imprinted polymers (Macromolecules 39, 7, 2460-2466) present a bewildering mass of data on the binding of substituted amino acids and small peptides by molecularly-imprinted polymers. Prepare an ‘executive summary’ of this information, answering the questions: (i) Have they really achieved anything useful? (ii) What are the most promising ways to extend what they have done in the direction of a useful product?
7. What are the principles of Isothermal Titration Calorimetry (ITC) and how might it be useful? Suggest some control experiments that South et al. (Macromolecules 39, 11, 3738) ought would have carried out as a preliminary to their ITC investigation of small-molecule binding to a complex terpolymer.
8. How would you prepare thermoresponsive magnetic microparticles suitable for use in aqueous solution at temperatures above 60ºC?
9. Predict, with reference to the equations of standard free-radical polymerisation kinetics, if the spatial patterning effects seen by Bryant, Hauch, and Ratner (Macromolecules, 39, 13, 4395 ) could be replicated with a high Tg polymer such as a photo-cured poly(methyl methacrylate). What would you expect to find different/the same in such a system?
10. Assume you have been given (nigh) unlimited resources to devote to the investigation of one current problem involving the control of free radical polymerisation. What problem do you chose to investigate? Outline an experimental plan for your investigations.
Time allowed: 24 hours from receipt of exam
Resources allowed: All, but you must cite all resources used in your answers.
Answer all questions.
1. (a) How do the properties of star polymers differ from linear polymers of the same molecular weight? Why? What applications does this make star polymers particularly suitable for? (b) Outline two schemes for producing star polymers of poly(butyl acrylate): one by a ‘core first’ approach and one by an ‘arm first’ approach.
2. “In the paper by Koumura et al. (Macromolecules 39, 12, 4060), Scheme 3 illustrates a process which is likely to be important in the stereoselective polymerisation of vinyl acetate in fluoroalcohol solvents.” Do you agree with this statement? Explain what Koumura et al. are trying to tell us in Scheme 3 and explain why you agree/disagree.
3. A company offers you a large sum of money to produce an electroactive actuator from poly(vinyl acetate). Either (i) explain how you would go about designing such an actuator for them or (ii) explain to them why they should not pursue such an idea.
4. Such, Evans, and Davis (Macromolecules 39, 4, 1391-1396) fit the decolouration of photochromic dyes in a polymer matrix to a biexponential distribution, A(t) = A1e–k1t + A2e–k2t + A∞. From their Table 2, what can you say about the variation in the five fitting parameters in this distribution with the physical properties of the polymer matrix? Do you think there are any good theoretical reasons for fitting the curves to a biexponential rather than a single exponential? Outline any reasons you think of and explain how they are consistent/inconsistent with the experimental data.
5. Fava et al. (Macromolecules 39, 5, 1665-1669) prepared core-shell polymer particles by surfactant-free emulsion polymerisation. Describe this process and what they did. They state that they lightly crosslinked both the core and shell of their particles: does this cast doubt on any of their conclusions? Explain.
6. Tables 1-4 of Osawa et al.’s work on molecularly-imprinted polymers (Macromolecules 39, 7, 2460-2466) present a bewildering mass of data on the binding of substituted amino acids and small peptides by molecularly-imprinted polymers. Prepare an ‘executive summary’ of this information, answering the questions: (i) Have they really achieved anything useful? (ii) What are the most promising ways to extend what they have done in the direction of a useful product?
7. What are the principles of Isothermal Titration Calorimetry (ITC) and how might it be useful? Suggest some control experiments that South et al. (Macromolecules 39, 11, 3738) ought would have carried out as a preliminary to their ITC investigation of small-molecule binding to a complex terpolymer.
8. How would you prepare thermoresponsive magnetic microparticles suitable for use in aqueous solution at temperatures above 60ºC?
9. Predict, with reference to the equations of standard free-radical polymerisation kinetics, if the spatial patterning effects seen by Bryant, Hauch, and Ratner (Macromolecules, 39, 13, 4395 ) could be replicated with a high Tg polymer such as a photo-cured poly(methyl methacrylate). What would you expect to find different/the same in such a system?
10. Assume you have been given (nigh) unlimited resources to devote to the investigation of one current problem involving the control of free radical polymerisation. What problem do you chose to investigate? Outline an experimental plan for your investigations.
2008 Exam
CHEM 400 Exam – Advanced Polymer Topics – 2008
Time allowed: 24 hours
Due back: 9 am Monday August 18th 2008
You may use any resource available anywhere in the world, but must cite all resources used.
Answer 10 questions.
Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene using novel heterocycle-containing chain transfer agents
Rajendran Prakash Babu and Raghavachari Dhamodharan
Polymer International, 57:365–371 (2008)
1. In Figure 9, there are a number of peaks in the 1H NMR which are not assigned, presumably arising from the end-groups derived from the R-group of the RAFT agents.
(a) Assign these peaks.
(b) The mechanism of RAFT polymerization suggests that one additional possible end-group should be observed in each of these three polymers. What is this end-group? Where should peaks arising from it be observed? Can you observe these peaks in the spectra, and is it surprising that you can/cannot?
(c) Are the NMR spectra consistent with the MN values quoted in the caption?
Noncovalent Cross-Linking of Poly(methyl methacrylate) via Polypseudorotaxane
Takayuki Nozaki, Takahiro Uno, Takahito Itoh, and Masataka Kubo
Macromolecules 2008, 41, 5186-5190
2. In this paper…
(a) Why are the products called ‘pseudopolyrotaxanes’ instead of polyrotaxanes? Suggest a procedure for converting them to polyrotaxanes. Can you think of any point in doing this?
(b) Explain what is happening in Figure 5. That is, what is the physical basis for the trend seen in going from prepolymer 1 to prepolymer 5? Is there a way you could present this figure differently to make the trend displayed easier to observe?
(c) How would you expect the dynamic mechanical properties of a pseudopolyrotaxane to differ from a conventional cross-linked polymer and conventional entangled polymer?
Site-Specific Dense Immobilization of Antibody Fragments on Polymer Brushes Supported by Silicone Nanofilaments
Yasuhiko Iwasaki, Yuki Omichi and Ryoko Iwata
Langmuir, doi: 10.1021/la801327a
3. In this work, antibodies are tethered to a surface by random copolymer brushes of 2-methacryloyloxyethy phosphorylcholine (MPC) and glycidyl methacrylate (GMA). What is the advantage of
(a) Tethering the antibodies to brushes, rather than attaching them directly to the surface?
(b) Using these rather complicated monomers in particular, instead of something cheaper?
The Synthesis and Properties of Carbazole-Phenylazomethine Double Layer-Type Dendrimers
Ken Albrecht, Yuto Kasai, Atsushi Kimoto, and Kimihisa Yamamoto
Macromolecules 2008, 41, 3793-3800
4. (a) How does an organic light emitting diode work? Please give diagrams and an explanation that would make sense to a student who had done CHEM 201 and CHEM 202, but no higher level chemistry.
(b) Define all the terms in Figures 6 and 9, and explain the differences in the luminescence vs. voltage curves in terms of the chemical and physical properties of the dendrimers used.
Complementary Hydrogen-Bonded Thermoreversible Polymer
Networks with Tunable Properties
Kamlesh P. Nair, Victor Breedveld and Marcus Weck
Macromolecules 2008, 41, 3429-3438
5. Most publications wishing to demonstrate that controlled polymerization is occurring will include a figure of ‘experimental molecular weight’ vs. ‘theoretical molecular weight’. Construct one of these for the data in Table 1. Does the figure look like it ought to? Why/why not?
6. Pretend you have been given the unenviable task of telling a class of Year Twelve Physics or Chemistry students what Figure 10 means and what information it is telling us about the two polymer networks. Make a Powerpoint presentation (or equivalent: you can draw on the board and take pictures, for instance) of no more than eight slides, writing down on the notes pages (or equivalent) everything you would say exactly as you would say it.
Effect of Molecular Weights of Poly(acrylic acid) on Crystallization of Calcium Carbonate by the Delayed Addition Method
Shu-Chen HUANG, Kensuke NAKA, and Yoshiki CHUJO
Polymer Journal, Vol. 40, No. 2, pp. 154–162, 2008
7. This paper is an examination of how calcium carbonate crystallization can be controlled by co-precipitation of hydrophilic polymers, in a simple model of the very complex process of biomineralisation.
(a) Compare and contrast the results obtained by adding polymer before the onset of crystallization, and after the onset of crystallization. Can you put forward a physical model (with diagrams) for what polyacrylic acid is doing in this system?
(b) One doomsday scenario associated with increasing anthropogenic carbon dioxide emissions is the ‘de-alkalinisation of the oceans’ and the effect this would have on marine life dependent on calcium carbonate. Write an argument using the results of this paper either to hype or downplay (I don’t mind which) this scenario.
Characterization of Oligo(vinyl phosphonate)s by High-Resolution Electrospray Ionization Mass Spectrometry: Implications for the Mechanism of Polymerization
Bahar Bingol, Gene Hart-Smith, Christopher Barner-Kowollik and Gerhard Wegner
Macromolecules 2008, 41, 1634-1639
8. How is the mechanism of polymerization of vinyl phosphonate unusual, according to the findings of this paper?
Nanohybrid Shish-Kebabs: Supercritical CO2-Induced PE Epitaxy on Carbon Nanotubes
Zhiwei Zhang, Qun Xu, Zhimin Chen and Jun Yue
Macromolecules 2008, 41, 2868-2873
9. (a) Discuss the statement: ‘Figure 6 is waaay dodgy.’
(b) During our discussion of this paper, we (well, I guess me, mostly) suggested an alternate explanation for how the observed structures are formed. What experiments could we carry out to see if this explanation or Scheme 2 was more like the truth?
(c) What is epitaxy, anyway? What advantages are there in using a fancy word like this? Are there any simpler words that could do the same job?
Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing
Balamurali Balu, Victor Breedveld, and Dennis W. Hess
Langmuir 2008, 24, 4785-4790
10. (a) Suggest why the contact angle hysteresis results obtained for the copy paper and the handsheet are different. How could you test this suggestion?
(b) What is XPS? What important information does it reveal in this paper?
Organo-Cobalt Mediated Living Radical Polymerization of Vinyl Acetate
Chi-How Peng, Jennifer Scricco, Shan Li, Michael Fryd, and Bradford B. Wayland
Macromolecules 2008, 41, 2368-2373
11. In Figure 9, the polymerization of vinyl acetate shows no inhibition period. In Figure 10, a marked inhibition period is seen for both vinyl acetate and methyl acrylate.
(a) How does this inhibition period arise?
(b) Why should it be different for methyl acrylate and vinyl acetate?
On the other hand, in Figure 9, retardation in the vinyl acetate polymerization rate is observed in the presence of the cobalt complex.
(c) Can a similar degree of retardation be seen in the polymerizations in Figure 10?
(d) If these polymerizations are significantly more or less retarded than the polymerization in the presence of the cobalt complex in Figure 9, explain why.
Time allowed: 24 hours
Due back: 9 am Monday August 18th 2008
You may use any resource available anywhere in the world, but must cite all resources used.
Answer 10 questions.
Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene using novel heterocycle-containing chain transfer agents
Rajendran Prakash Babu and Raghavachari Dhamodharan
Polymer International, 57:365–371 (2008)
1. In Figure 9, there are a number of peaks in the 1H NMR which are not assigned, presumably arising from the end-groups derived from the R-group of the RAFT agents.
(a) Assign these peaks.
(b) The mechanism of RAFT polymerization suggests that one additional possible end-group should be observed in each of these three polymers. What is this end-group? Where should peaks arising from it be observed? Can you observe these peaks in the spectra, and is it surprising that you can/cannot?
(c) Are the NMR spectra consistent with the MN values quoted in the caption?
Noncovalent Cross-Linking of Poly(methyl methacrylate) via Polypseudorotaxane
Takayuki Nozaki, Takahiro Uno, Takahito Itoh, and Masataka Kubo
Macromolecules 2008, 41, 5186-5190
2. In this paper…
(a) Why are the products called ‘pseudopolyrotaxanes’ instead of polyrotaxanes? Suggest a procedure for converting them to polyrotaxanes. Can you think of any point in doing this?
(b) Explain what is happening in Figure 5. That is, what is the physical basis for the trend seen in going from prepolymer 1 to prepolymer 5? Is there a way you could present this figure differently to make the trend displayed easier to observe?
(c) How would you expect the dynamic mechanical properties of a pseudopolyrotaxane to differ from a conventional cross-linked polymer and conventional entangled polymer?
Site-Specific Dense Immobilization of Antibody Fragments on Polymer Brushes Supported by Silicone Nanofilaments
Yasuhiko Iwasaki, Yuki Omichi and Ryoko Iwata
Langmuir, doi: 10.1021/la801327a
3. In this work, antibodies are tethered to a surface by random copolymer brushes of 2-methacryloyloxyethy phosphorylcholine (MPC) and glycidyl methacrylate (GMA). What is the advantage of
(a) Tethering the antibodies to brushes, rather than attaching them directly to the surface?
(b) Using these rather complicated monomers in particular, instead of something cheaper?
The Synthesis and Properties of Carbazole-Phenylazomethine Double Layer-Type Dendrimers
Ken Albrecht, Yuto Kasai, Atsushi Kimoto, and Kimihisa Yamamoto
Macromolecules 2008, 41, 3793-3800
4. (a) How does an organic light emitting diode work? Please give diagrams and an explanation that would make sense to a student who had done CHEM 201 and CHEM 202, but no higher level chemistry.
(b) Define all the terms in Figures 6 and 9, and explain the differences in the luminescence vs. voltage curves in terms of the chemical and physical properties of the dendrimers used.
Complementary Hydrogen-Bonded Thermoreversible Polymer
Networks with Tunable Properties
Kamlesh P. Nair, Victor Breedveld and Marcus Weck
Macromolecules 2008, 41, 3429-3438
5. Most publications wishing to demonstrate that controlled polymerization is occurring will include a figure of ‘experimental molecular weight’ vs. ‘theoretical molecular weight’. Construct one of these for the data in Table 1. Does the figure look like it ought to? Why/why not?
6. Pretend you have been given the unenviable task of telling a class of Year Twelve Physics or Chemistry students what Figure 10 means and what information it is telling us about the two polymer networks. Make a Powerpoint presentation (or equivalent: you can draw on the board and take pictures, for instance) of no more than eight slides, writing down on the notes pages (or equivalent) everything you would say exactly as you would say it.
Effect of Molecular Weights of Poly(acrylic acid) on Crystallization of Calcium Carbonate by the Delayed Addition Method
Shu-Chen HUANG, Kensuke NAKA, and Yoshiki CHUJO
Polymer Journal, Vol. 40, No. 2, pp. 154–162, 2008
7. This paper is an examination of how calcium carbonate crystallization can be controlled by co-precipitation of hydrophilic polymers, in a simple model of the very complex process of biomineralisation.
(a) Compare and contrast the results obtained by adding polymer before the onset of crystallization, and after the onset of crystallization. Can you put forward a physical model (with diagrams) for what polyacrylic acid is doing in this system?
(b) One doomsday scenario associated with increasing anthropogenic carbon dioxide emissions is the ‘de-alkalinisation of the oceans’ and the effect this would have on marine life dependent on calcium carbonate. Write an argument using the results of this paper either to hype or downplay (I don’t mind which) this scenario.
Characterization of Oligo(vinyl phosphonate)s by High-Resolution Electrospray Ionization Mass Spectrometry: Implications for the Mechanism of Polymerization
Bahar Bingol, Gene Hart-Smith, Christopher Barner-Kowollik and Gerhard Wegner
Macromolecules 2008, 41, 1634-1639
8. How is the mechanism of polymerization of vinyl phosphonate unusual, according to the findings of this paper?
Nanohybrid Shish-Kebabs: Supercritical CO2-Induced PE Epitaxy on Carbon Nanotubes
Zhiwei Zhang, Qun Xu, Zhimin Chen and Jun Yue
Macromolecules 2008, 41, 2868-2873
9. (a) Discuss the statement: ‘Figure 6 is waaay dodgy.’
(b) During our discussion of this paper, we (well, I guess me, mostly) suggested an alternate explanation for how the observed structures are formed. What experiments could we carry out to see if this explanation or Scheme 2 was more like the truth?
(c) What is epitaxy, anyway? What advantages are there in using a fancy word like this? Are there any simpler words that could do the same job?
Fabrication of “Roll-off” and “Sticky” Superhydrophobic Cellulose Surfaces via Plasma Processing
Balamurali Balu, Victor Breedveld, and Dennis W. Hess
Langmuir 2008, 24, 4785-4790
10. (a) Suggest why the contact angle hysteresis results obtained for the copy paper and the handsheet are different. How could you test this suggestion?
(b) What is XPS? What important information does it reveal in this paper?
Organo-Cobalt Mediated Living Radical Polymerization of Vinyl Acetate
Chi-How Peng, Jennifer Scricco, Shan Li, Michael Fryd, and Bradford B. Wayland
Macromolecules 2008, 41, 2368-2373
11. In Figure 9, the polymerization of vinyl acetate shows no inhibition period. In Figure 10, a marked inhibition period is seen for both vinyl acetate and methyl acrylate.
(a) How does this inhibition period arise?
(b) Why should it be different for methyl acrylate and vinyl acetate?
On the other hand, in Figure 9, retardation in the vinyl acetate polymerization rate is observed in the presence of the cobalt complex.
(c) Can a similar degree of retardation be seen in the polymerizations in Figure 10?
(d) If these polymerizations are significantly more or less retarded than the polymerization in the presence of the cobalt complex in Figure 9, explain why.
2009 Exam
CHEM 400 Exam – Advanced Polymer Topics – 2009
Time allowed: 24 hours
Due back: 9 am Monday July 13th 2009
Work independently of your fellow Honours students.
Otherwise, you may use any resource available anywhere in the world, but must cite all resources used.
Part One. Answer all questions associated with any six of the nine papers below. (60%)
1. Structure and Properties of Composite Antibacterial PET Fibers
Wang Shuhua, Hou Wensheng, Wei Liqiao, Dai Jinming, Jia Husheng, Liu Xuguang, Xu Bingshe
These researchers work in Taiyuan, a city a visiting academic we had at the University of Sydney once proudly told me was the most polluted in the world.
What should the units of tensile strength be in Table III? Explain how these values were measured and why they might show the trend they do with loading of silica nanoparticles.
What is the double refraction index, Δn? Why should it show a positive correlation to break strength and a negative correlation to extensibility? Explain how the Δn results are consistent/inconsistent with the X-ray diffraction and tensile strength results.
As a scientist interested in polymers and colloids, what is one additional experiment you would have done before publishing this work?
2. The Furan Counterpart of Poly(ethylene terephthalate): An Alternative Material Based on Renewable Resources
Alessandro Gandini, Armando J. D. Silvestre, Carlos Pascoal Neto, Andreia F. Sousa, Mónica Gomes
I have never heard of Aveiro, where the University of Aveiro appears to be located. Has anything interesting ever happened there? Is there anyone famous who comes from Aveiro?
Explain the necessity for ‘concurrent trapping of the released ethylene glycol at liquid nitrogen temperature’.
Explain what is physically happening at the ‘crystallisation isotherm’ in Figure 3.
The authors have explained the origin of the broad background signal in PEF after quenching in Figure 4, but why do you think there are more sharp peaks in the X-ray diffractogram of PEF after quenching than before quenching? Explain and identify the peaks as fully as you can.
As a scientist interested in polymers, what is one additional experiment you would have done before publishing this work?
3. Polygalactose Containing Nanocages: The RAFT Process for the Synthesis of Hollow Sugar Balls
S. R. Simon Ting, Andrew M. Gregory, and Martina H. Stenzel
I applied for a job with this group just around Christmas 2003, but UNSW had put the wrong email address in the advertisement so it bounced back. It was the last day, and for whatever reason- there was some technical glitch or other- I decided ‘stuff it’ and didn’t send the application again.
Explain, with reference to as many chemical structures of RAFT intermediates as are relevant, why the slopes of the three curves in Figure 1 are different and why the induction times before they start are different.
How does the Brookhaven Zetaplus particle determine hydrodynamic diameter? What is hydrodynamic diameter, anyway?
If one of your students was using SEC traces like the ones shown in this paper to calculate polydispersity, what would you say to them?
4. Plasticization of Zein: A Thermomechanical, FTIR, and Dielectric Study
Thomas Gillgren, Susan A. Barker, Peter S. Belton, Dominique M. R. Georget, and Mats Stading
Steve had some students from Gothenburg come and work with him some years ago. As late as the 17th century, Norwich was the second largest city in England. But I don’t really know anything about either of those places.
What do you think is going on with the (lack of) plasticisation by mercaptoethanol in these experiments?
Explain what complex permittivity is and what is going on in Figures 8 and 9. Use as many equations as you have to!
What is Maxwell-Wagner dispersion? Suggest one other experiment that might be done to check for the presence of bulk water in these systems.
5. Exploring the Liquid-like Layer on the Ice Surface
M. P. Goertz, X.-Y. Zhu, and J. E. Houston
When I was young we used to live near Minneapolis. I used to have to walk a mile in the snow to catch the school bus. I was in two school bus accidents where we slid off the icy road into ditches. I think we might have got a different school bus driver after the second one.
What do you see as the most significant experimental uncertainties hanging over this work?
Suggest an explanation for the abnormally high viscosity value for the liquid like layer given by the Feibelman equation. Is this viscosity consistent with the macroscopic properties of ice?
Explain what is going on in Figure 3(b). Is the statement ‘the accurate characterization of this “frustrated-capillary” behavior involves a rather sophisticated hydrodynamic model and is certainly beyond the scope of this contribution’ just a hand-waving cop-out, or what?
As a scientist interested in messing about with ice, what is one additional experiment you would have done before publishing this work?
6. Assembly of Self-Assembled Monolayer-Coated Al2O3 on TiO2 Thin Films for the Fabrication of Renewable Superhydrophobic-Superhydrophilic Structures
Shunsuke Nishimoto, Hitomi Sekine, Xintong Zhang, Zhaoyue Liu, Kazuya Nakata, Taketoshi Murakami, Yoshihiro Koide, and Akira Fujishima
I know this guy from uni in Townsville who worked in admin at UTS for a while and then met a Japanese girl and moved to somewhere in greater Tokyo- which probably isn’t actually anywhere near where these guys work. The girlfriend he had before the Japanese girl didn’t like this giant paper mache dog he had that apparently used to hang from the ceiling in a nightclub in Perth, so I said I would take it and it currently takes up a lot of space in my dining room.
What is the significance of the following result: ‘(advancing CA: 167°; receding CA: 152°; CA hysteresis: 15°). Specifically, why is contact angle hysteresis important?
Can you find any experimental justification out there for the assertion that superhydrophilicity is lost due to adsorption of hydrocarbons from the atmosphere? If so, outline the experimental results that have been obtained. If not, suggest an alternative explanation for the loss of superhydrophilicity over time.
What is the point of fluid microchips? Will they change the world? If so, how?
7. Complex Micelles Formed from Two Diblock Copolymers for Applications in Controlled Drug Release
Guiying Li, Lei Guo, Songmei Ma, Junshen Liu
Can’t remember if I ever told you my anecdote about Yantai or not. Just in case, I won’t bore you with it a second time.
Explain the results shown in Figure 7, explaining why the release profiles are the way they are for the different complex micelles.
What is a Janus-micelle? Is it really accurate to call such a thing a micelle?
If you had done this work, how would you have reported the polymer characterisation results differently? What additional information would you have presented and what methods would you have used to get this information?
8. Pattern Formation in PMMA Film Induced by Electric Field
Oleksiy Lyutakov, Ivan Hüttel, Václav Prajzler, Vítěslav Jeřábek, Alexander Jančárek, Vladimír Hnatowicz, Václav Švorčík
How are you supposed to pronounce an ‘ě’, anyhow?
Explain how the different channel profiles obtained in Figure 3 and Figure 6 might arise.
This paper reports primarily on the characterisation of the surface of the PMMA films. What differences might you expect to find in the bulk film between patterned and unpatterned films, and what characterisation methods would you employ to observe these?
The work reported here seems to have certain similarities with ‘electrospinning’. What is electrospinning? What do you expect might have happened if the researchers had just kept cranking up the electric field?
9. Preparation and Characterization of Multiwalled Carbon Nanotube Dispersions in Polypropylene: Melt Mixing Versus Solid-State Shear Pulverization
Saswati Pujari, Thillaiyan Ramanathan, Kosmas Kasimiatis, Jun’ichi Masuda, Rodney Andrews, John M. Torkelson, Catherine Brinson, Wesley R. Burghardt
There was a chemist at USyd whose name I can’t remember right now who got his PhD at Northwestern, he looked like King Henry VIII on graduation days, it was the most fantastically opulent male garment I have ever seen outside of the movies.
In Figure 7, what is q? What is the main thing the figure telling us, and why/how does this work? What information might be theoretically obtainable from the parts of the curve at extreme left and extreme right?
What is the storage modulus, G'? How is the frequency dependence of G' related to chain entanglements? Explain what is going on at the molecular level to give the results shown in Figure 2.
As a scientist interested in why the mechanical and electrical properties are different for the two different methods of dispersing carbon nanotubes, what is one additional experiment you would have done before publishing this work?
Part Two: Answer all questions associated with any three of the six papers below. (25%)
10. Stabilization of Enzymes in Silk Films
Shenzhou Lu, Xiaoqin Wang, Qiang Lu, Xiao Hu, Neha Uppal, Fiorenzo G. Omenetto, and David L. Kaplan
With most biological materials, the higher the water content, the more rapid degradation processes can occur. In this work, however, the trend is the opposite way around. Why is this?
Pretend you are one of those lame science-fiction writers of the old school who puts in big blocks of exposition explaining the new technology postulated in the story. Write a paragraph of exposition describing a gee-whiz technical innovation based on the research in this paper and explaining how it works for the folks at home.
11. Non-cytotoxic Silver Nanoparticle-Polysaccharide Nanocomposites with Antimicrobial Activity
Andrea Travan, Chiara Pelillo, Ivan Donati, Eleonora Marsich, Monica Benincasa, Tommaso Scarpa, Sabrina Semeraro, Gianluca Turco, Renato Gennaro, and Sergio Paoletti
What is a “surface plasmon resonance band”? I am sure I have had it explained to me a number of times but it has never sunk in properly, so use small easy words.
Do the results in this paper fully assuage any fears you might have about the cytotoxicity of silver nanoparticles? Suggest some additional experimental tests to reassure yourself (if you answered no), or some timid people you know (if you answered yes), that might be worth trying before you licensed this technology for commercial applications.
12. Inactivation of Bacterial Pathogens by Carbon Nanotubes in Suspensions
L. Renea Arias and Liju Yang
Outline the different results obtained for inactivation of bacterial pathogens by SNTs chemically-modified in different ways. How do the authors explain these differences, and the differences between SWNTs and MWNTs? Can you think of any other possibilities to explain the differences?
In chemical terms, what is the difference between Gram-positive and Gram-negative bacteria? How do these chemical differences relate to the environments where these bacteria might be found?
13. Using the Flotation of a Single Sphere to Measure and Model Capillary Forces
C. W. Extrand, and Sung In Moon
An old and wise scientist I know once (well, often) told me: ‘Just because the model fits the data, it doesn’t mean the model is true.’ Is there anything important left out of the model given that really should be there to give a complete physical picture of what is going on? Is there anything included that doesn’t make a great difference to the predictions obtained but makes the equations much more complicated?
What does the model predict Rmax to be for a PTFE sphere in water with a surface modified to be superhydrophobic?
14. Design of Surface Hierarchy for Extreme Hydrophobicity
Yongjoo Kwon, Neelesh Patankar, Junkyu Choi, and Junghoon Lee
You have probably heard of SNU in connection with ‘Snuppy’, the first cloned dog.
This paper talks quite a lot about the transition between the Wenzel state and the Cassie state. What are these states?
Most of our encounters of superhydrophobicity have discussed plane surfaces. What are some potential applications of superhydrophobicity to fibres, and what are some of the pitfalls that we might need to watch out for in trying to achieve these applications?
15. Innovative Approach for Producing Injectable, Biodegradable Materials Using Chitooligosaccharides and Green Chemistry
Luciano F. Boesel, Rui L. Reis and Julio San Román
My only connection with this group is that I cited them once.
To what extent do you think the products discussed in this paper are actually ‘biodegradable’? To what extent do you think the chemistry is actually ‘green’? Naturally, justify your assertions.
Tell me all about MALDI-TOF and its application to polymers. How is it different from other mass spectrometry techniques?
Part Three (15%)
And finally...
Of all the papers we have read this semester, which line of research would you be most interested in investigating further is someone gave you $5 million to continue on from one of them? What major questions would you seek to answer and what experiments would you initially carry out to work toward answering these questions?
Time allowed: 24 hours
Due back: 9 am Monday July 13th 2009
Work independently of your fellow Honours students.
Otherwise, you may use any resource available anywhere in the world, but must cite all resources used.
Part One. Answer all questions associated with any six of the nine papers below. (60%)
1. Structure and Properties of Composite Antibacterial PET Fibers
Wang Shuhua, Hou Wensheng, Wei Liqiao, Dai Jinming, Jia Husheng, Liu Xuguang, Xu Bingshe
These researchers work in Taiyuan, a city a visiting academic we had at the University of Sydney once proudly told me was the most polluted in the world.
What should the units of tensile strength be in Table III? Explain how these values were measured and why they might show the trend they do with loading of silica nanoparticles.
What is the double refraction index, Δn? Why should it show a positive correlation to break strength and a negative correlation to extensibility? Explain how the Δn results are consistent/inconsistent with the X-ray diffraction and tensile strength results.
As a scientist interested in polymers and colloids, what is one additional experiment you would have done before publishing this work?
2. The Furan Counterpart of Poly(ethylene terephthalate): An Alternative Material Based on Renewable Resources
Alessandro Gandini, Armando J. D. Silvestre, Carlos Pascoal Neto, Andreia F. Sousa, Mónica Gomes
I have never heard of Aveiro, where the University of Aveiro appears to be located. Has anything interesting ever happened there? Is there anyone famous who comes from Aveiro?
Explain the necessity for ‘concurrent trapping of the released ethylene glycol at liquid nitrogen temperature’.
Explain what is physically happening at the ‘crystallisation isotherm’ in Figure 3.
The authors have explained the origin of the broad background signal in PEF after quenching in Figure 4, but why do you think there are more sharp peaks in the X-ray diffractogram of PEF after quenching than before quenching? Explain and identify the peaks as fully as you can.
As a scientist interested in polymers, what is one additional experiment you would have done before publishing this work?
3. Polygalactose Containing Nanocages: The RAFT Process for the Synthesis of Hollow Sugar Balls
S. R. Simon Ting, Andrew M. Gregory, and Martina H. Stenzel
I applied for a job with this group just around Christmas 2003, but UNSW had put the wrong email address in the advertisement so it bounced back. It was the last day, and for whatever reason- there was some technical glitch or other- I decided ‘stuff it’ and didn’t send the application again.
Explain, with reference to as many chemical structures of RAFT intermediates as are relevant, why the slopes of the three curves in Figure 1 are different and why the induction times before they start are different.
How does the Brookhaven Zetaplus particle determine hydrodynamic diameter? What is hydrodynamic diameter, anyway?
If one of your students was using SEC traces like the ones shown in this paper to calculate polydispersity, what would you say to them?
4. Plasticization of Zein: A Thermomechanical, FTIR, and Dielectric Study
Thomas Gillgren, Susan A. Barker, Peter S. Belton, Dominique M. R. Georget, and Mats Stading
Steve had some students from Gothenburg come and work with him some years ago. As late as the 17th century, Norwich was the second largest city in England. But I don’t really know anything about either of those places.
What do you think is going on with the (lack of) plasticisation by mercaptoethanol in these experiments?
Explain what complex permittivity is and what is going on in Figures 8 and 9. Use as many equations as you have to!
What is Maxwell-Wagner dispersion? Suggest one other experiment that might be done to check for the presence of bulk water in these systems.
5. Exploring the Liquid-like Layer on the Ice Surface
M. P. Goertz, X.-Y. Zhu, and J. E. Houston
When I was young we used to live near Minneapolis. I used to have to walk a mile in the snow to catch the school bus. I was in two school bus accidents where we slid off the icy road into ditches. I think we might have got a different school bus driver after the second one.
What do you see as the most significant experimental uncertainties hanging over this work?
Suggest an explanation for the abnormally high viscosity value for the liquid like layer given by the Feibelman equation. Is this viscosity consistent with the macroscopic properties of ice?
Explain what is going on in Figure 3(b). Is the statement ‘the accurate characterization of this “frustrated-capillary” behavior involves a rather sophisticated hydrodynamic model and is certainly beyond the scope of this contribution’ just a hand-waving cop-out, or what?
As a scientist interested in messing about with ice, what is one additional experiment you would have done before publishing this work?
6. Assembly of Self-Assembled Monolayer-Coated Al2O3 on TiO2 Thin Films for the Fabrication of Renewable Superhydrophobic-Superhydrophilic Structures
Shunsuke Nishimoto, Hitomi Sekine, Xintong Zhang, Zhaoyue Liu, Kazuya Nakata, Taketoshi Murakami, Yoshihiro Koide, and Akira Fujishima
I know this guy from uni in Townsville who worked in admin at UTS for a while and then met a Japanese girl and moved to somewhere in greater Tokyo- which probably isn’t actually anywhere near where these guys work. The girlfriend he had before the Japanese girl didn’t like this giant paper mache dog he had that apparently used to hang from the ceiling in a nightclub in Perth, so I said I would take it and it currently takes up a lot of space in my dining room.
What is the significance of the following result: ‘(advancing CA: 167°; receding CA: 152°; CA hysteresis: 15°). Specifically, why is contact angle hysteresis important?
Can you find any experimental justification out there for the assertion that superhydrophilicity is lost due to adsorption of hydrocarbons from the atmosphere? If so, outline the experimental results that have been obtained. If not, suggest an alternative explanation for the loss of superhydrophilicity over time.
What is the point of fluid microchips? Will they change the world? If so, how?
7. Complex Micelles Formed from Two Diblock Copolymers for Applications in Controlled Drug Release
Guiying Li, Lei Guo, Songmei Ma, Junshen Liu
Can’t remember if I ever told you my anecdote about Yantai or not. Just in case, I won’t bore you with it a second time.
Explain the results shown in Figure 7, explaining why the release profiles are the way they are for the different complex micelles.
What is a Janus-micelle? Is it really accurate to call such a thing a micelle?
If you had done this work, how would you have reported the polymer characterisation results differently? What additional information would you have presented and what methods would you have used to get this information?
8. Pattern Formation in PMMA Film Induced by Electric Field
Oleksiy Lyutakov, Ivan Hüttel, Václav Prajzler, Vítěslav Jeřábek, Alexander Jančárek, Vladimír Hnatowicz, Václav Švorčík
How are you supposed to pronounce an ‘ě’, anyhow?
Explain how the different channel profiles obtained in Figure 3 and Figure 6 might arise.
This paper reports primarily on the characterisation of the surface of the PMMA films. What differences might you expect to find in the bulk film between patterned and unpatterned films, and what characterisation methods would you employ to observe these?
The work reported here seems to have certain similarities with ‘electrospinning’. What is electrospinning? What do you expect might have happened if the researchers had just kept cranking up the electric field?
9. Preparation and Characterization of Multiwalled Carbon Nanotube Dispersions in Polypropylene: Melt Mixing Versus Solid-State Shear Pulverization
Saswati Pujari, Thillaiyan Ramanathan, Kosmas Kasimiatis, Jun’ichi Masuda, Rodney Andrews, John M. Torkelson, Catherine Brinson, Wesley R. Burghardt
There was a chemist at USyd whose name I can’t remember right now who got his PhD at Northwestern, he looked like King Henry VIII on graduation days, it was the most fantastically opulent male garment I have ever seen outside of the movies.
In Figure 7, what is q? What is the main thing the figure telling us, and why/how does this work? What information might be theoretically obtainable from the parts of the curve at extreme left and extreme right?
What is the storage modulus, G'? How is the frequency dependence of G' related to chain entanglements? Explain what is going on at the molecular level to give the results shown in Figure 2.
As a scientist interested in why the mechanical and electrical properties are different for the two different methods of dispersing carbon nanotubes, what is one additional experiment you would have done before publishing this work?
Part Two: Answer all questions associated with any three of the six papers below. (25%)
10. Stabilization of Enzymes in Silk Films
Shenzhou Lu, Xiaoqin Wang, Qiang Lu, Xiao Hu, Neha Uppal, Fiorenzo G. Omenetto, and David L. Kaplan
With most biological materials, the higher the water content, the more rapid degradation processes can occur. In this work, however, the trend is the opposite way around. Why is this?
Pretend you are one of those lame science-fiction writers of the old school who puts in big blocks of exposition explaining the new technology postulated in the story. Write a paragraph of exposition describing a gee-whiz technical innovation based on the research in this paper and explaining how it works for the folks at home.
11. Non-cytotoxic Silver Nanoparticle-Polysaccharide Nanocomposites with Antimicrobial Activity
Andrea Travan, Chiara Pelillo, Ivan Donati, Eleonora Marsich, Monica Benincasa, Tommaso Scarpa, Sabrina Semeraro, Gianluca Turco, Renato Gennaro, and Sergio Paoletti
What is a “surface plasmon resonance band”? I am sure I have had it explained to me a number of times but it has never sunk in properly, so use small easy words.
Do the results in this paper fully assuage any fears you might have about the cytotoxicity of silver nanoparticles? Suggest some additional experimental tests to reassure yourself (if you answered no), or some timid people you know (if you answered yes), that might be worth trying before you licensed this technology for commercial applications.
12. Inactivation of Bacterial Pathogens by Carbon Nanotubes in Suspensions
L. Renea Arias and Liju Yang
Outline the different results obtained for inactivation of bacterial pathogens by SNTs chemically-modified in different ways. How do the authors explain these differences, and the differences between SWNTs and MWNTs? Can you think of any other possibilities to explain the differences?
In chemical terms, what is the difference between Gram-positive and Gram-negative bacteria? How do these chemical differences relate to the environments where these bacteria might be found?
13. Using the Flotation of a Single Sphere to Measure and Model Capillary Forces
C. W. Extrand, and Sung In Moon
An old and wise scientist I know once (well, often) told me: ‘Just because the model fits the data, it doesn’t mean the model is true.’ Is there anything important left out of the model given that really should be there to give a complete physical picture of what is going on? Is there anything included that doesn’t make a great difference to the predictions obtained but makes the equations much more complicated?
What does the model predict Rmax to be for a PTFE sphere in water with a surface modified to be superhydrophobic?
14. Design of Surface Hierarchy for Extreme Hydrophobicity
Yongjoo Kwon, Neelesh Patankar, Junkyu Choi, and Junghoon Lee
You have probably heard of SNU in connection with ‘Snuppy’, the first cloned dog.
This paper talks quite a lot about the transition between the Wenzel state and the Cassie state. What are these states?
Most of our encounters of superhydrophobicity have discussed plane surfaces. What are some potential applications of superhydrophobicity to fibres, and what are some of the pitfalls that we might need to watch out for in trying to achieve these applications?
15. Innovative Approach for Producing Injectable, Biodegradable Materials Using Chitooligosaccharides and Green Chemistry
Luciano F. Boesel, Rui L. Reis and Julio San Román
My only connection with this group is that I cited them once.
To what extent do you think the products discussed in this paper are actually ‘biodegradable’? To what extent do you think the chemistry is actually ‘green’? Naturally, justify your assertions.
Tell me all about MALDI-TOF and its application to polymers. How is it different from other mass spectrometry techniques?
Part Three (15%)
And finally...
Of all the papers we have read this semester, which line of research would you be most interested in investigating further is someone gave you $5 million to continue on from one of them? What major questions would you seek to answer and what experiments would you initially carry out to work toward answering these questions?
2007 Exam
CHEM 400 Exam – Advanced Polymer Topics
Time allowed: 24 hours
You can consult any resource in the world, but cannot collaborate with each other.
Answer part (a) for all questions and part (b) for four questions. 50% of the mark will be on part (a) and 50% on part (b).
1. Solvent-Free Synthesis of Pseudopolyrotaxane and Polyrotaxane: Efficient Threading Complexation of a Cyclodextrin Wheel and a Linear Polymer Axle to Yield Pseudopolyrotaxane and its Fixation to Polyrotaxane by the Direct Grinding of a Solid Mixture
Runtao Liu, Takeshi Maeda, Nobuhiro Kihara, Akira Harada, Toshikazu Takata, J. Polym. Sci. A, 2007, 45, 1571-1574
(a) Explain the trends in yield and coverage ratio obtained with variation in polymer molecular weight in terms of the entropy of the physical and chemical processes involved.
(b) In the introduction, it is stated that it has been demonstrated that rotaxane formation of these compounds is possible only on solid-solid mixing, and not in the presence of a solvent. Is this a valid interpretation of the previous work? Can you think of mechanisms that would make these results plausible?
2. Morphological, Electrical, and Mechanical Characterization of Electrospun Nanofibre Mats Containing Multiwalled Carbon Nanotubes
Seth D. McCullen, Derrick R. Stevens, Wesley A. Roberts, Satjayeet S. Ojha, Laura I. Clarke, Russell E. Gorga, Macromolecules, 2007, 40, 997-1003
(a) Explain the technique of electrospinning in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Explain the Fournier model for conductance. What is the physical meaning of the parameters derived using this model in the system of McCullen et al.?
3. Synthesis and Properties of Helical Polyacetylenes carrying Cholesteryl Moieties
Jinqinq Qu, Masashi Shiotsuki, Fumio Sanda, Toshio Masuda, 2007, Macrom. Chem. Phys., 2007, 208, 823-832
(a) Explain the technique of circular dichroism in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Outline the mechanism of polymerisation in this paper. Give the structures of all chemical species involved and explain their role in the polymerisation.
4. Preparation of Poly(butylene-co-epsilon-caprolactone carbonate) [Microspheres?] and Their Use as Drug Carriers for a Controlled Delivery System
Yanfei Liu, Kelong Huang, Dongming Peng, Suqin liu, Hong Wu, J. Polym. Sci. A, 2007, 45, 2152-2160
(a) Give an explanation for the trends in all copolymer properties measured as the caprolactone content of the material is varied (pp.2156-2157).
(b) Are the 1H NMR assignments in Figure 2 credible? Independently reassess these assignments. Does this have any implications for the results?
5. Chemical Synthesis of Polyaniline Inverse Opals by Templating Colloidal Crystals in the Presence of Dodecylbenzenesulfonic Acid
Ling-Yueh Yang, Wen-Bin Liau, Macromol. Chem. Phys., 2007, 208, 994-1001
(a) Outline the mechanism for the chemical polymerisation of aniline used in this work.
(b) How might including dodecylbenzyl sulfonic acid reduce ‘shrinkage’ of the materials? Suggest a strategy for making more robust inverse opals with thicker poly(aniline) walls.
6. Simplified polymer mimics of crosslinking adhesive proteins
Glenn Westwood, Trinity N. Horton, Jonathan J. Wilker, Macromolecules, 2007, 40, 3960-3964
(a) How do you suppose the oxidising crosslinkers work? What chemical bond is formed? Explain the relative effectiveness of the crosslinkers employed with reference to your mechanism.
(b) All samples in this work displayed cohesive failure. Why might it be more interesting to examine adhesive failure? Design experimental conditions which might make it more likely to measure the adhesive strength of the polymers.
7. Optically Active Polychromism in Polyanilines
Hiromasa Goto, J. Polym. Sci. Chem., 45, 2085-2090
(a) Explain the technique of cyclic voltammetry in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Explain why reduction of the polyaniline leads to a planar rather than helical conformation. How might this effect be useful? Describe a possible application and some of the hurdles that would need to be overcome before it became a realistic possibility.
8. Composite Electrolytes for Lithium Batteries: Ionic Liquids in APTES Cross-Linked Polymers
Dean M. Tigelaar, Mary Ann B. Meador, William R. Bennett, Macromolecules, 2007, 40, 4159-4164
(a) Draw a flow diagram giving the chemical structure of each of the components of Polymer C and explaining the role of each compound in the synthesis.
(b) Make up a question on this paper of equivalent complexity to the other part (b) questions, and answer it.
9. Electric-Field-Controlled Synthesis of HPMA Hydrogels Containing Self-Organised Arrays of Micro-Channels.
Tedric D. Campbell, Randy P. Washington, Oliver Steinbock, J. Polym. Sci. Chem., 45, 2593-2600
(a) Draw a flow diagram giving the chemical structure of each of the components of the structured HPMA hydrogels and explaining the role of each compound in the synthesis.
(b) Campbell, Washington, and Steinbeck have only varied one variable in obtaining different morphologies- the amount of poly(ethylene glycol) used. How would you expect the morphology to change with:
(i) the relative amount of methylene-bis-acrylamide?
(ii) the relative amount of N-acryloyl glycine?
(iii) the molecular weight of poly(ethylene glycol)?
10. Functionalisation of Gold and Silicon Surfaces by Copolymer Brushes using Surface-Initiated ATRP
Ekaterina Rakhmatullina, Thomas Braun, Thomas Kaufmann, Hannes Spillmann, Violeta Malinova, Wolfgang Meier, Macromol. Chem. Phys., 2007, 208, 1283-1293.
(a) Explain the technqiue of ellipsometry in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Suggest a reason the polymer –brush surface might have the morphology shown in Figure 2. How might you go about testing your hypothesis?
Time allowed: 24 hours
You can consult any resource in the world, but cannot collaborate with each other.
Answer part (a) for all questions and part (b) for four questions. 50% of the mark will be on part (a) and 50% on part (b).
1. Solvent-Free Synthesis of Pseudopolyrotaxane and Polyrotaxane: Efficient Threading Complexation of a Cyclodextrin Wheel and a Linear Polymer Axle to Yield Pseudopolyrotaxane and its Fixation to Polyrotaxane by the Direct Grinding of a Solid Mixture
Runtao Liu, Takeshi Maeda, Nobuhiro Kihara, Akira Harada, Toshikazu Takata, J. Polym. Sci. A, 2007, 45, 1571-1574
(a) Explain the trends in yield and coverage ratio obtained with variation in polymer molecular weight in terms of the entropy of the physical and chemical processes involved.
(b) In the introduction, it is stated that it has been demonstrated that rotaxane formation of these compounds is possible only on solid-solid mixing, and not in the presence of a solvent. Is this a valid interpretation of the previous work? Can you think of mechanisms that would make these results plausible?
2. Morphological, Electrical, and Mechanical Characterization of Electrospun Nanofibre Mats Containing Multiwalled Carbon Nanotubes
Seth D. McCullen, Derrick R. Stevens, Wesley A. Roberts, Satjayeet S. Ojha, Laura I. Clarke, Russell E. Gorga, Macromolecules, 2007, 40, 997-1003
(a) Explain the technique of electrospinning in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Explain the Fournier model for conductance. What is the physical meaning of the parameters derived using this model in the system of McCullen et al.?
3. Synthesis and Properties of Helical Polyacetylenes carrying Cholesteryl Moieties
Jinqinq Qu, Masashi Shiotsuki, Fumio Sanda, Toshio Masuda, 2007, Macrom. Chem. Phys., 2007, 208, 823-832
(a) Explain the technique of circular dichroism in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Outline the mechanism of polymerisation in this paper. Give the structures of all chemical species involved and explain their role in the polymerisation.
4. Preparation of Poly(butylene-co-epsilon-caprolactone carbonate) [Microspheres?] and Their Use as Drug Carriers for a Controlled Delivery System
Yanfei Liu, Kelong Huang, Dongming Peng, Suqin liu, Hong Wu, J. Polym. Sci. A, 2007, 45, 2152-2160
(a) Give an explanation for the trends in all copolymer properties measured as the caprolactone content of the material is varied (pp.2156-2157).
(b) Are the 1H NMR assignments in Figure 2 credible? Independently reassess these assignments. Does this have any implications for the results?
5. Chemical Synthesis of Polyaniline Inverse Opals by Templating Colloidal Crystals in the Presence of Dodecylbenzenesulfonic Acid
Ling-Yueh Yang, Wen-Bin Liau, Macromol. Chem. Phys., 2007, 208, 994-1001
(a) Outline the mechanism for the chemical polymerisation of aniline used in this work.
(b) How might including dodecylbenzyl sulfonic acid reduce ‘shrinkage’ of the materials? Suggest a strategy for making more robust inverse opals with thicker poly(aniline) walls.
6. Simplified polymer mimics of crosslinking adhesive proteins
Glenn Westwood, Trinity N. Horton, Jonathan J. Wilker, Macromolecules, 2007, 40, 3960-3964
(a) How do you suppose the oxidising crosslinkers work? What chemical bond is formed? Explain the relative effectiveness of the crosslinkers employed with reference to your mechanism.
(b) All samples in this work displayed cohesive failure. Why might it be more interesting to examine adhesive failure? Design experimental conditions which might make it more likely to measure the adhesive strength of the polymers.
7. Optically Active Polychromism in Polyanilines
Hiromasa Goto, J. Polym. Sci. Chem., 45, 2085-2090
(a) Explain the technique of cyclic voltammetry in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Explain why reduction of the polyaniline leads to a planar rather than helical conformation. How might this effect be useful? Describe a possible application and some of the hurdles that would need to be overcome before it became a realistic possibility.
8. Composite Electrolytes for Lithium Batteries: Ionic Liquids in APTES Cross-Linked Polymers
Dean M. Tigelaar, Mary Ann B. Meador, William R. Bennett, Macromolecules, 2007, 40, 4159-4164
(a) Draw a flow diagram giving the chemical structure of each of the components of Polymer C and explaining the role of each compound in the synthesis.
(b) Make up a question on this paper of equivalent complexity to the other part (b) questions, and answer it.
9. Electric-Field-Controlled Synthesis of HPMA Hydrogels Containing Self-Organised Arrays of Micro-Channels.
Tedric D. Campbell, Randy P. Washington, Oliver Steinbock, J. Polym. Sci. Chem., 45, 2593-2600
(a) Draw a flow diagram giving the chemical structure of each of the components of the structured HPMA hydrogels and explaining the role of each compound in the synthesis.
(b) Campbell, Washington, and Steinbeck have only varied one variable in obtaining different morphologies- the amount of poly(ethylene glycol) used. How would you expect the morphology to change with:
(i) the relative amount of methylene-bis-acrylamide?
(ii) the relative amount of N-acryloyl glycine?
(iii) the molecular weight of poly(ethylene glycol)?
10. Functionalisation of Gold and Silicon Surfaces by Copolymer Brushes using Surface-Initiated ATRP
Ekaterina Rakhmatullina, Thomas Braun, Thomas Kaufmann, Hannes Spillmann, Violeta Malinova, Wolfgang Meier, Macromol. Chem. Phys., 2007, 208, 1283-1293.
(a) Explain the technqiue of ellipsometry in a manner comprehensible to a student who has done only first year chemistry and physics. Diagrams and equations will be looked upon favourably.
(b) Suggest a reason the polymer –brush surface might have the morphology shown in Figure 2. How might you go about testing your hypothesis?
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