One-pot synthesis of POSS-containing alternating copolymers by RAFT polymerization and their microphase-separated nanostructures

The poly(styrene-alt-maleimide isobutyl POSS) (PSMIPOSS) alternating copolymer is one-pot synthesized via reversible addition-fragmentation transfer (RAFT) polymerization. The results show that a POSS-containing alternating copolymer with a high degree of polymerization (DP) and a low polydispersity index (PDI) is successfully constructed by alternating copolymerization of maleimide isobutyl POSS with styrene, and the molecular weight of the PSMIPOSS alternating copolymer can be well controlled by the amount of RAFT agent. Poly(styrene-alt-maleimide isobutyl POSS)-block-polystyrene (PSMIPOSS-b-PS) block copolymers are also one-pot prepared by RAFT polymerization, and their self-assembly behavior in the bulk is investigated by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS), which exhibit a series of short-range order phase transitions from the POSS sphere, POSS cylinder to lamella structures with the weight fraction of MIPOSS ranging from 13% to 64%. The thermal properties of POSS-containing copolymers are evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The results display that MIPOSS units can enhance the thermal properties of copolymers effectively.