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Some polymer physics at small N
The polymerisation index, N, is one of the most important parameter in determining polymer behavior. A large majority of work in polymer science focuses on large N, where the polymer molecules behave almost like random chains. I will present some of our recent experimental findings using near oligomeric polystyrene with small (<10) N. It is well know and accepted that atactic polystyrene is a strictly amorphous material. I will show our measurements of crystallization in atactic polystyrene for small N and discuss what our measurements may mean in terms of finding analogous crystallization in higher molecular weight atactic polystyrenes. Then I will discuss our recent results using evaporative purification of small N polymers. Polymers produced by anionic polymerisation –the gold standard of making monodisperse polymers– give rise to polydispersity (Mw/Mn-1 ) 0.01. Our technique allows for the production of samples with polydispersities which are potentially many of orders of magnitude better. These samples provide exciting opportunities to study how properties such as the glass transition temperature vary with N.