Synthesis and Properties of Multi-stimuli-Responsive Water-Soluble Hyperbranched Polymers Prepared Via Reversible Addition–Fragmentation Chain Transfer Self-Condensing Vinyl Polymerization

Multistimuli-responsive hyperbranched polymers were synthesized in one-step polymerization using reversible addition–fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP). These hyperbranched polymers responded to UV–vis or sunlight, pH changes, and temperature changes. 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid known as DDMAT participated in esterification with 2-hydroxyethyl methacrylate to obtain a chain transfer monomer in the name of 2-((2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoyl)oxy)ethylmethacrylate (MACDT). For the first time, smart hyperbranched polymers were produced with the RAFT-SCVP method in one step by using 2-(dimethylamino)ethyl methacrylate (DMAEMA), spirooxazine acryloyl monomer, and MACDT with different feed ratios ([DMAEMA]/[MACDT]). Moreover, smart hyperbranched polymers prepared by the RAFT-SCVP method reveal the manner of controlling molecular weights and the degree of branching (DB). Additionally, this study shows that when the DB of polymers was increased or feed ratios were decreased, photochromic properties and the lower critical solution temperature point of hyperbranched polymers were reduced. Furthermore, these smart hyperbranched polymers have the potential to be utilized as sensors.