Dhiraj, Harpal (2022) Lactate and glucose-responsive nanoparticles by reversible addition-fragmentation chain transfer (RAFT) polymerizations. (PhD thesis), Kingston University, .
Abstract
Ch. 1 is the background to preparing precision polymers using reversible addition-fragmentation chain transfer (RAFT). Ch. 2-5 describe original primary research. Introduction Ch. 2 and 3 overview RAFT homogeneous polymerizations of 3-(acrylamidophenyl)boronoic acid (3-BAPhA) and polymerization induced self-assembly (PISA) of free boronic acid (BA) substituted monomers. Ch. 4 rationalizes approaches for the synthesis of glucose and lactate responsive nanoparticles. Ch. 5 reviews the use of BA in polymer morphology transitions. Methods Ch. 2 describes the synthesis of 3-BAPhA and its pinacol ester (3-BAEPhA) derivative, along with the para-analogue (4-BAEPhA) monomer and compares RAFT with N-phenylacrylamide (PhA). Ch. 3 describes the synthesis of poly(N,N-dimethylacrylamide) macroRAFT steric stabilizers and protocols for RAFT-mediated dispersion polymerizations of 3-BAPhA. Ch. 4 and 5 describe protocols for one-pot iterative RAFT polymerizations of acrylamides and dialysis approaches to self-assembly. Results RAFT polymerizations of 3-BAPhA give similar control/living character to PhA and 3-BAEPhA with 4-BAEPhA polymerizations slower. Ch. 3 describes the first PISA on an unprotected BA-monomer with transitions to higher order morphologies upon dilution with the dispersion solvent. PISA of 3-BAEPhA gave spherical particles, worms, and vesicles. Ch. 4 shows lactate binding at pH = 7.4 leads to comparable effects on morphology to that of glucose binding at pH = 8.7. The first direct formation of pure worms for the self-assembly of free BA polymer was found. Ch. 5 describes lactate and glucose induced self-assembly of solvated hydrophobic polymers containing poly(3-BAPhA) block. Conclusions Ch. 2 optimized the conditions for RAFT polymerization of BA-substituted acrylamides. Ch. 3 is published in Polymer Chemistry 2022, 13, 3750-3755 and achieved new smart nanoparticles, which undergo sphere-to-worm transitions upon hydrolysis of boroxine moieties. Ch. 4 and 5 establishes lactate as a stimulus for self-assembly of amphiphilic and hydrophobic polyacrylamides respectively.
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