Scaffold Design for Photogrowable Nanonetworks and Pre-Evaluation for Orthogonal Nanoparticle Expansion

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2021-12-03

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Abstract

A substantial part of polymer chemistry focuses on the formation of block copolymers for functionalization. These polymers possess a wide range of characteristics based on how they are constructed and polymerized. Recently, the focus in this field has shifted to the formation of nanoparticles. Harth’s research group has led the way in creating photogrowable nanonetworks (PGNNs). There is an inherent difficulty in conducting orthogonal expansion polymerizations once a PGNN is formed. The challenge of PGNN is to conduct controlled polymerizations that expand either from the scaffold or crosslinker without affecting each other or any end groups. This project covers the formation of various scaffolds for PGNNs with varying properties, and pre-evaluation polymerization reactions involving symmetrical trithiocarbonate crosslinkers to conduct orthogonal polymerizations on nanoparticles involving these scaffolds and crosslinkers. Scaffolds were constructed using reversible-addition fragmentation chain transfer (RAFT) polymerization, or atom transfer radical polymerization (ATRP). The preliminary reactions that tested the crosslinkers were performed with catalyst ZnTPP under green light and with methyl acrylate as the monomer. Several control reactions were performed to examine the orthogonality of the nanonetwork polymerizations. The construction of the scaffolds provided three different designs for expansion methods and different attachment methods for the crosslinkers. Evaluation tests performed on the crosslinkers demonstrated that orthogonal polymerization can be achieved on a PGNN. This project contributed to the formation of three different design scaffolds for future PGNNs and controlled reactions that demonstrate orthogonal expansion of the individual components of photogrowable networks.

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nanoparticles, nanonetworks, scaffolds, crosslinkers, polymer chemistry, orthogonal polymerization, trithiocarbonates, RAFT, PET-RAFT, ATRP, PGNN, photogrowth, nanoparticle expansion, chain extension, end group removal, block copolymers, networks, biochemistry

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