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?