Synthesis of Amphiphilic Helix–Coil–Helix Poly(3-(glycerylthio)propyl isocyanate)-block-polystyrene-block-poly(3-(glycerylthio)propyl isocyanate)

To achieve molecular packing of protic-functionalized helical polymers in aqueous solution, we synthesized an amphiphilic helix–coil–helix triblock copolymer (triBCP) composed of polystyrene and dihydroxyl-functionalized polyisocyanates. Poly(3-(glycerylthio)propyl isocyanate)- block -polystyrene- block -poly(3-(glycerylthio)propyl isocyanate), P3GPIC- b -PSt- b -P3GPIC, was synthesized by postpolymerization modification. The bidirectional anionic block copolymerization of styrene (St) and allyl isocyanate (AIC) yielded triBCPs, poly(allyl isocyanate)- block -polystyrene- block -poly(allyl isocyanate)s (PAIC- b -PSt- b -PAICs), with well-controlled molecular weights ( M n = 5.60–99.9 kDa) and narrow dispersities ( Đ = 1.14–1.18). Of them, one with the lowest MW ( M n = 5.60 kDa, Đ = 1.14), which was highly organic-soluble, was utilized in the thiol–ene click reaction between allyl group and 1-thioglycerol, producing P3GPIC- b -PSt- b -P3GPIC. The amphiphilic P3GPIC- b -PSt- b -P3GPIC self-aggregated to form spherical vesicles with an average hydrodynamic diameter of 170 nm in aqueous solution, demonstrating that hydrophilic–helical P3GPIC blocks well interacted with water media maintaining their intermolecular packing.