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-tert-butylstyrene)(PEO_(113)-b-PVBC_(130)-b-Pt BS_(x)or E_(113)V_(130)T_(x))triblock terpolymers with various lengths x(=20,33,66,104,215)of Pt 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 Pt BS blocks strongly hindered the crystallization of PEO block.The effects of Pt 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 from20 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℃.

Amphiphilic ABC Triblock Terpolymer Templating for Mesoporous Silica

Self-assembled triblock terpolymers have attracted intense attention in recent years because of their abundant variety of assembly mesostructure. We reported the synthesis of mesoporous silica materials with the am- phiphilic ABC triblock terpolymer polyethylene-poly（ethylene oxide）-polycaprolactone（PE-PEO-PCL） as a template and tetraethoxysilane（TEOS） as a silica source. Increasing the hydrophilic head group（PEO） led to the decrease of packing parameter g, which gave rise to the mesophase transformation from a cylindrical two-dimensional hexagonal P6mm structure to a cage-type face centered cubic closed-packing mesostructure. This new templating route provided a new insight into the template factor governed inorganic-organic self-assembly mesophases.