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Thermoreversible Order−Order Transition of a Triblock Copolymer Containing a Mesogen‐Jacketed Liquid Crystalline Polymer with a Re‐Entrant Phase Behavior
Author(s) -
Pan Yu,
Shi LingYing,
Ping Jing,
Zhang Zhenyu,
Gu Kehua,
Fan XingHe,
Shen Zhihao
Publication year - 2016
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201500514
Subject(s) - copolymer , polymer chemistry , materials science , lamellar structure , polystyrene , polymer , phase (matter) , polymerization , glass transition , amorphous solid , phase transition , chemical engineering , crystallography , chemistry , composite material , organic chemistry , thermodynamics , physics , engineering
Poly{2,5‐bis[(4‐butoxyphenyl)‐oxycarbonyl]styrene} (PBPCS) with a re‐entrant phase behavior is used to synthesize a new kind of ABC triblock copolymers (triBCPs), poly(dimethylsiloxane)‐ b ‐polystyrene‐ b ‐PBPCS (PDMS‐ b ‐PS‐ b ‐PBPCS, DSB). Two well‐defined triBCPs D 120 S 100 B 50 and D 120 S 100 B 120 with different molecular weights (MWs) and narrow MW distributions are synthesized by sequential atom transfer radical polymerization. The volume fractions of PDMS, PS, and PBPCS in D 120 S 100 B 50 are 0.24, 0.26, and 0.50, respectively, while the values in D 120 S 100 B 120 are 0.14, 0.16, and 0.70, respectively. At low temperatures, PBPCS is amorphous. Both samples form a core–shell hexagonally packed cylindrical (CSH) morphology. At high temperatures, PBPCS in the triBCPs can form a liquid crystalline (LC) phase, the transformation of which can induce an order−order transition (OOT) of D 120 S 100 B 120 . The nanostructure changes from a CSH structure to a three‐phase‐four‐layer lamellar structure, and the transition is thermoreversible. The sequence of the OOT is opposite to that of a coil−coil−coil triBCP. The unusual LC behavior of PBPCS plays an important role on the thermoreversible morphological transition of the triBCP.