During the past several years my students and I have been utilizing small-molecule hosts [cyclodestrins and urea] to nanostructure polymers. This is accomplished by first forming non-covalently bonded inclusion complexes (ICs) between these small-molecule hosts and guest polymers, followed by the careful removal of the host molecule crystalline lattice to obtain a coalesced bulk polymer. We have repeatedly observed such coalesced polymer samples to behave distinctly from those produced from their solutions or melts. Coalesced amorphous homopolymers exhibit higher glass-transition temperatures, while crystallizable coalesced homopolymers evidence higher melting and crystalliz-ation temperatures, and sometimes different crystalline polymorphs. When ICs are formed with block copolymers or with two or more different homopolymers the resulting coalesced samples can evidence intimate mixing between the copolymer blocks or between entire homopolymer chains, respectively. All the distinct behaviors observed for polymers coalesced from their ICs is a conseq-uence of the structural organization of polymer-host-ICs. Polymer chains in IC crystals are confined to occupy narrow diameter (~0.5 – 1.0nm) channels formed by the crystallization of the small-molecule hosts around the guest polymers. This results in the high extension and separation of guest polymer chains, which leads to unique behaviors for bulk coalesced polymer samples. In addition, when excess polymer is used to form ICs with CD hosts, non-stoichiometric [(n-s)] ICs, with partially un-included chains, are formed. We will describe several applications for polymers coalesced from their ICs and for (n-s)-polymer-CD-ICs.

Restructuring polymers<i> via</i> nano-confinement and subsequent release

253rd National Meeting (2017)

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Restructuring polymers via nano-confinement and subsequent release