We report the synthesis of a series of statistical terpolymer poly[(methyl methacrylate)-co-lauryl methacrylate-co-2-((3,5-bis(4-carbamoyl-3-(trifluoromethyl)phenoxy)benzyloxy)carbonylamino)ethyl methacrylate] (P(MMA-co-LMA-co-BMA)) by reversible addition–fragmentation chain transfer polymerization and their aggregation behaviors in solution. In toluene, the solution behavior of terpolymer was controlled by the molar fractions of lauryl methacrylate (LMA) and benzamide-containing methacrylate (BMA) in the polymer, which increased solubility and promoted hydrogen bonding between the primary aromatic amides, respectively. Temperature-dependent 1H NMR spectroscopy also indicated gradual dissociation of the hydrogen bonds with increasing temperature. For the polymer containing 2.7 mol % of LMA and 2.7 mol % of BMA repeating units, we demonstrated that dissolving the polymer in tetrahydrofuran as a good solvent and switching the solvent with toluene produced polymer nanoparticles with diameters of several tens of nanometers, as observed by dynamic light scattering. Intramolecular hydrogen bonding was dominant and induced the noncovalent chain collapse. When the temperature of the particle dispersion in toluene at a concentration > 30 mg/mL was increased from RT to 50 °C, a significant increase in viscosity was observed. This behavior was not observed in a toluene solution of poly(methyl methacrylate), which showed decreased viscosity at a higher temperature. The viscosity increase was accompanied by a decrease in the particle size, and both were attributed to the dissociation of some intramolecular hydrogen bonds within the particles, which can increase the number of individual chains in toluene and result in more intermolecular interactions.

The viscosity of poly(styrene)-b-poly(lactide) [PS-b-PLA] solutions in a neutral solvent was characterized by magnetic microrheology. The effect of polymer concentration on the viscosity of the block polymer solutions was compared with that of the PS and PLA homopolymers in the same solvent. The viscosity of PS-b-PLA solution, unlike the homopolymer solutions, showed a steep increase over a narrow concentration range. The steep rise was concomitant with microphase separation into an ordered cylindrical microstructure as determined by small-angle X-ray scattering. Hence microrheology proved effective as a means of characterizing the order–disorder transition concentration. During an in situ drying experiment, changes in local viscosity through the depth of a block copolymer solution were characterized as a function of drying time. Early in the drying process, the viscosity rose steadily and was uniform through the depth, a result consistent with steadily increasing and uniform polymer concentration. However, later in the drying process as the overall polymer concentration approached that required for microphase separation, the viscosity of the polymer solution near the free surface became an order of magnitude higher than that near the bottom of the container. The zone of high viscosity moved downward as drying proceeded, consistent with a microphase separation front.