Sequence-Regulated Alternating Copolymers: Synthesis, Characterization, Solid and Solution State Properties

Goswami, Krishna Gopal (2020) Sequence-Regulated Alternating Copolymers: Synthesis, Characterization, Solid and Solution State Properties. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Krishna Gopal Goswami (15RS052)) 15RS052.pdf - Submitted Version Restricted to Repository staff only Download (6MB)

Abstract

Monomer sequence control along the polymer chain is an important aspect of polymer research since the polymer properties depend both on the monomer constitution and their arrays, which eventually determine the higher-order polymer conformations as well as the polymeric bulk properties and applications as witnessed in various natural biopolymers, for example, proteins, DNA and RNA. Literature reports suggest the extensive preparation of sequence defined polymeric materials through iterative, step-growth, chain-growth, template and multiblock chain shuttling mechanism to yield periodic patterns. In this context, alternating copolymers are the simplest form of sequence controlled polymers where the two comonomers are placed in a regular exchanging fashion. The Alternating distribution of monomers throughout the polymer chain can be steadily accomplished by simple copolymerization of a set of monomers having dissimilar electronic specifications through multiple controlled or living polymerization methods. Amongst the various well-explored monomer pairs, styrene and N-functionalized maleimides are most investigated and often preferred to design alternating architectures as these can be easily functionalized with a variety of required entities. Nowadays, functionalities like amino acids, fatty acids and peptides are widely used to design an extensive range of block or random copolymers with significant assets and applications. However, the properties associated with their alternating architecture have not been broadly studied. Herein, we will discuss the preparation of semi-crystalline alternating copolymers from fatty acid attached maleimide and methoxy poly(ethylene glycol) (mPEG) tethered styrene monomers followed by the study of their side chain crystalline properties. We will also discuss the solution state self-assembly behaviour of these alternating copolymers depending on the identity of the fatty acid and mPEG side chains. Apart from that, we will demonstrate the synthesis of alternating copolymers possessing an alternative placement of amino acids (D- and L-alanine) or dipeptides (glycyl-glycine and alanyl-alanine) in the side chain of the polymers followed by study of their corresponding physical properties.

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