(150f) Effects of Surfactant HLB Values and Charges on the Phase Transition Behavior of Thermoresponsive Polysaccharides

Understanding how different types of surfactants interact with thermoresponsive polymers is critical to regulate phase transition temperatures and control polymer aggregation behavior, offering opportunities in generating microparticles for drug delivery applications. Here we developed a novel class of synthetic thermoresponsive polysaccharides through chemically converting hydrophilic polymer backbone to hydrophobic derivatives. These thermoresponsive materials exhibit robust and reversible phase transition and tunable lower critical solution temperatures. We evaluated the impacts of different surfactants including anionic sodium dodecyl sulfate (SDS), nonionic pluronic, cationic hexadecyltrimethylammonium bromide (CTAB), and zwitterionic 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) on the phase transition of non-charged polysaccharides. We discovered that the temperature-triggered hydrophobic interactions and phase transition behaviors are controlled by surfactant charge density, hydrophilic—lipophilic balance (HLB) values and critical micelle concentrations (CMC). Surfactants with higher HLB values dramatically disrupt phase separation above their CMC concentrations. Non-ionic pluronic F127 surfactant effectively eliminates phase transitions across a wide range of dextran molecular weights and concentrations even below surfactant CMC concentration. These findings will expand the selection of appropriate surfactants to regulate the polymer/polymer or polymer/solvent interactions to modulate phase-separation and fabricate microstructured biomaterials for cancer drug delivery.