An all-optical photorefractive miktoarm star polymer synthesized via a combination of RAFT polymerization and click reaction

Aiming to obtain effective calix[4]resorcinarene (CRA)-based photorefractive (PR) materials, three star polymers CRA-PCAH4, CRA-PCAH8 and CRA-PCAH4-PCH4 were prepared via a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and click reaction. CRA-PCAH4 and CRA-PCAH8 bearing only carbazole-azo-nitrobenzene-based polymeric arms exhibited poor solubility in low boiling point solvents because of the strong interchain electrostatic interactions. While the miktoarm star polymer CRA-PCAH4-PCH4, which was prepared based on CRA-PCAH4 by introducing some carbazole-based polymer arms (PCH) as buffering chains to isolate the nonlinear optical (NLO) components in the CRA core, exhibited good solubility in tetrahydrofuran (THF). A composite based on CRA-PCAH4-PCH4 showed much better PR performance than that of the corresponding PCAH arm tested via a two-beam coupling (TBC) experiment under zero electric field without pre-poling.