Characterization of diblock copolymer order-order transitions in semidilute aqueous solution using fluorescence correlation spectroscopy

The temperature and pH-dependent diffusion of poly(glycerol monomethacrylate)-block-poly(2-hydroxypropyl methacrylate) nanoparticles prepared via polymerization-induced self-assembly in water is characterized using fluorescence correlation spectroscopy (FCS). Lowering the solution temperature or raising the solution pH induces a worm-to-sphere transition and hence an increase in diffusion coefficient by a factor of between four and eight. FCS enables morphological transitions to be monitored at relatively high copolymer concentrations (10% w/w) compared to those required for dynamic light scattering (0.1% w/w). This is important because such transitions are reversible at the former concentration, whereas they are irreversible at the latter. Furthermore, the FCS data suggest that the thermal transition takes place over a very narrow temperature range (less than 2 °C). These results demonstrate the application of FCS to characterize order-order transitions, as opposed to order-disorder transitions. The temperature and pH-dependent diffusion of poly(glycerol monomethacrylate)-block-poly(2-hydroxypropylmethacrylate)- nanoparticles in water is characterized using fluorescence correlation spectroscopy. Lowering either the solution temperature or pH induces a worm-to-sphere transition and hence an increase in diffusion coefficient by a factor of between four and eight

“Grafting to” as a Novel and Simple Approach for Triple-Shape Memory Polymers

Maleated-polystyrene-<i>b</i>-poly­(ethylene-co-butylene)-<i>b</i>-polystyrene (m-SEBS) is a block copolymer with two melting temperatures belonging to soft poly­(ethylene-co-butylene) (EB) and hard polystyrene (PS) segments. As EB segments contain anhydride reactive groups, this allows grafting polybutylene succinate (PBS) as another soft segment to m-SEBS backbone to obtain triple-shape memory polymers based on two transition temperatures, i.e., <i>T</i>_m values of EB (at 55–65 °C) and PBS (at 105–115 °C). The present work shows a novel and simple approach of “grafting to” to develop triple-shape memory polymers

“Grafting to” as a Novel and Simple Approach for Triple-Shape Memory Polymers

Maleated-polystyrene-<i>b</i>-poly­(ethylene-co-butylene)-<i>b</i>-polystyrene (m-SEBS) is a block copolymer with two melting temperatures belonging to soft poly­(ethylene-co-butylene) (EB) and hard polystyrene (PS) segments. As EB segments contain anhydride reactive groups, this allows grafting polybutylene succinate (PBS) as another soft segment to m-SEBS backbone to obtain triple-shape memory polymers based on two transition temperatures, i.e., <i>T</i>_m values of EB (at 55–65 °C) and PBS (at 105–115 °C). The present work shows a novel and simple approach of “grafting to” to develop triple-shape memory polymers