Self-assembly of amphiphilic block pendant polymers for microphase separation materials and folded flower micelles
Herein, we created amphiphilic polymers bearing hydrophilic/hydrophobic block pendants as a new class of self-assembled materials for microphase separation in the solid state and folded flower micelles in water. For this, we designed amphiphilic block methacrylates comprising a hydrophilic poly(ethylene glycol) (PEG) and a hydrophobic dodecyl group: DPEG10MA and DPEG23MA. DPEG10MA or DPEG23MA homopolymers induced microphase separation of the pendent blocks. For example, a DPEG23MA homopolymer formed lamellar structures; the hydrophilic and crystalized PEG and hydrophobic dodecyl units are alternatingly layered with about 14 nm domain spacing. In water, random copolymers of PEG methyl ether methacrylate and DPEG10MA folded into flower micelles with both looped and linear PEG shells, where the dodecyl groups of the incorporated DPEG10MA assembled to form hydrophobic cores. The micelles further showed thermoresponsive solubility in water. The size, aggregation number, and cloud point of the micelles were controlled by composition and chain length.