Small‐Angle X‐Ray Scattering Studies of Block Copolymer Nano‐Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization‐Induced Self‐Assembly

We report that polymerization-induced self-assembly (PISA) can be used to prepare lyotropic phases comprising diblock copolymer nano-objects in non-polar media. RAFT dispersion polymerization of benzyl methacrylate (BzMA) at 90 °C using a trithiocarbonate-capped hydrogenated polybutadiene (PhBD) steric stabilizer block n-dodecane produces either spheres or worms exhibit long-range order 40 % w/w solids. NMR studies enable calculation instantaneous compositions for each phase during the BzMA polymerization. As PBzMA chains grow longer when targeting PhBD80–PBzMA40, time-resolved small-angle X-ray scattering reveals intermediate body-centered cubic (BCC) and hexagonally close-packed (HCP) sphere prior formation final hexagonal cylinder (HEX). The HEX is lost on serial dilution aligned cylinders eventually form disordered flexible worms. undergoes an order–disorder transition heating 150 pure HCP forms cooling 20 °C.