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. All the distinct behaviors observed for polymers coalesced from their ICs is a con-sequence 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. 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 of coalescence from their ICs and formation of their (n-s)-ICs for synthetic polymers used in medical devices.   <br/>

Restructuring polymers for medical devices <i>via</i> nano-confinement in and subsequent release from cyclodextrin and urea inclusion compounds

251st National Meeting (2016)

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Restructuring polymers for medical devices via nano-confinement in and subsequent release from cyclodextrin and urea inclusion compounds