Rotaxanated Polymers: I. Synthesis and Purification of Cyclic Polydimethylsiloxane II. Synthesis of Poly[octene-pseudorotaxa-(a-cyclodextrin)]
White, Bryan M.
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Polyrotaxanes possess a molecular architecture resembling that of a wheel and axle: linear polymer chains are threaded by cyclic molecules with no covalent bonds linking the two species. One of two methods can be employed for the preparation of polyrotaxanes: a template method to guide threading or an in situ polymerization of monomers in the presence of cyclic molecules. The research described in this dissertation was divided into two distinct sections, which were devoted to each method of polyrotaxane preparation. The first step of synthesizing polyrotaxanes via the in situ polymerization method was to prepare a cyclic molecule. Î±,Ï -Dihydroxy-PDMS was cyclized and then efficiently purified by an anion-exchange resin to remove uncyclized, yet anionically charged, linear PDMS. The second part of this dissertation included examining polyrotaxanes created by the template-directed threading of Î±-CD onto polyoctene (PO). End-capped PO, which was unthreadable by Î±-CD, was synthesized from 1,9-decadiene and a monovinyl bulky compound by acyclic diene metathesis. PO and ecPO each were sonicated in aqueous solutions of Î± -CD; PO formed a white precipitate indicative of a rotaxanated polymer, but no precipitate formed by the addition of ecPO. These results provided evidence that PO had been included within the cavity of Î±-CD.