Novel Thermoresponsive and pH-Responsive Aggregates from Self-Assembly of Triblock Copolymer PSMA-b-PNIPAAm-b-PSMA

Abstract

A series of novel triblock copolymers of poly(stearyl methacrylate)-b-poly(N-isopropylacrylamide)-b-poly(stearyl methacrylate) (PSMA-b-PNIPAAm-b-PSMA) with different molecular weights was synthesized through carboxyl-terminated trithiocarbonates as a highly efficient RAFT agent via reversible addition-fragmentation chain transfer (RAFT) polymerization. The resultant polymers were characterized by 1H NMR, FT-IR spectroscopy, and GPC. By varying the organic solvent used in the self-assembly procedure and adjusting the copolymer composition, multiple morphologies ranging from vesicles and core-shell spherical aggregates with different dimensions to pearl-necklace-like aggregates were obtained. The aggregates showed thermoresponsive and pH-responsive properties through the lower critical solution temperature (LCST) of PNIPAAm and the two carboxyl end groups of the copolymer.

Synthesis and solution rheology of poly[(stearyl methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)]

“…After modification with methyl iodide, the polymers became cationic, whereafter their solubility in organic solvents was strongly reduced, so that the polymers precipitated from the reaction solvent [23]. Typically polymers with an amphiphilic character can be dissolved in water by first dissolving them in a solvent mixture followed by evaporation of the co-solvent [16]. In this study homogeneous solutions were achieved by heating to above the solubility temperature after careful homogenisation of water and the polymer.…”

“…The solubility of the polymer is also strongly dependent on molecular weight. Polymethacrylates with controlled molecular weights can be prepared by group transfer polymerisation [14], atom transfer radical polymerisation [15], reversible addition-fragmentation chain transfer polymerisation [4,16], ring opening polymerisation, etc. SMA can also be polymerised through photopolymerisation [17].…”

Synthesis and aggregation behavior of chitooligosaccharide‐based biodegradable graft copolymers

“…It is known that the morphology and dimension of the formed copolymer aggregates via self‐assembly are strongly dependent on the copolymer structure and concentration, the nature of the used solvent, pH, and many other factors 32–35. In this article, we mainly study the factors such as the copolymer structure, the copolymer concentration, and the self‐assembly process on the morphologies of the resulting COS‐ g ‐PCL aggregates.…”

Fabrication of polymer-hollow sphere optical-functional hybrid material via RAFT polymerization

“…[22,23]. 3-Aminopropyltriethoxysilane (KH550, 99%) was purchased from Shanghai Aladdin Chemical Reagent Co. Ltd. All other chemical reagents were of analytical grade and used without further purification.…”