Effect of poly(4‑tert-butylstyrene) block length on the microphase structure of poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4‑tert-butylstyrene) triblock terpolymers

A series of linear poly(ethylene oxide)- b -poly(4-vinylbenzyl chloride)- b -poly(4‑ ter t-butylstyrene) (PEO 113 - b -PVBC 130 - b -P t BS x or E 113 V 130 T x ) triblock terpolymers with various lengths x (=20, 33, 66, 104, 215) of P t BS block were synthesized via a two-step reversible addition-fragmentation chain transfer (RAFT) polymerization. The E 113 V 130 T x triblock terpolymers were non-crystalline because the PVBC and P t BS blocks strongly hindered the crystallization of PEO block. The effects of P t BS block length x on the phase structures of E 113 V 130 T x triblock terpolymers were investigated by combined techniques of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). It was found that with increasing x from 20 to 215, the phase structure of E 113 V 130 T x triblock terpolymers became more ordered and changed from disordered structure , hexagonally-packed cylinder (HEX), hexagonally perforated layer (HPL), to lamellar (LAM) phase structures. Temperature-variable SAXS measurements showed that the HEX, HPL and LAM phase structures obtained for E 113 V 130 T 66 , E 113 V 130 T 104 and E 113 V 130 T 215 by thermal annealing, respectively, were thermodynamically stable in the temperature range of 30–170 °C.