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Thermal changes in the association behavior of poly(ethylene oxide)-poly(propylene oxide) alternating multiblock (PEO-PPO AMB) copolymers in water are investigated by the use of transmittance and light scattering measurements. Two PEO-PPO AMB copolymers with a different weight fraction of PEO, (EOPO) and (EOPO), are prepared. The weight-average molecular weights of (EOPO) and (EOPO) estimated by static light scattering measurements are 1.3 × 10 and 4.1 × 10 g mol, respectively. The number of PEO-PPO repeating pairs is over 8. It is found that the aqueous solution of (EOPO) undergoes phase separation with a lower critical solution temperature (LCST) of around 58 °C at 0.3 wt %. For the aqueous (EOPO) solution, the LCST is estimated to be ca. 42 °C. The critical solution concentration for (EOPO) is not clear because of a small concentration dependence of T at a higher concentration range. Dynamic light scattering measurements indicate that a micellelike aggregate is formed below the LCST. From the Debye plot, it is elucidated that the second virial coefficient, A, starts going down at around 32 °C for (EOPO) and below 15 °C for (EOPO). The A value of (EOPO) approaches 0 near 50 °C, whereas that of (EOPO) approaches 0 at around 35 °C. At a high temperature, the attractive interaction among the copolymers becomes dominant, thereby inducing the formation of micellelike aggregates.

The “carbohydrate module method” is a promising approach for oligosaccharide mimetics using polymeric materials. However, it is difficult to predict the optimal structure for a particular oligosaccharide mimetic, and an...

Introduction Thermoresponsive polymers are a class of smart materials. The properties of such polymers change significantly in a controlled fashion under the influence of external stimuli 1. To develop synthetic polymer systems that act as protein mimics is a great challenge for polymer scientists. The block design of copolymers is an effective strategy for preparing protein mimics using synthetic polymers 2. An alternative way is to control the monomer sequence, which corresponds to the primary structure of proteins 3. However, the interaction among the monomers often makes it difficult to predict the macroscopic properties of the final products 4, 5. In comparison with monomer sequence control, the block design is advantageous for achieving predictable physicochemical properties of the resultant copolymer and scale-up of the preparation process. Because the individual blocks in the copolymer may retain the characteristics of the homopolymer, the numerous reports on the homopolymers may serve as a block library 6 19. Recently, we investigated the solution properties of amphiphilic alternating multiblock AMB copolymers. The