Premium
Kinetically Trapped Block Copolymer Nano‐Objects with Cylinder to Sphere Shape Transition Properties
Author(s) -
Li Yuyan,
Peng Bo,
Chen Yongming
Publication year - 2015
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.201400505
Subject(s) - copolymer , cylinder , polystyrene , materials science , kinetic energy , polymer , morphology (biology) , polymer chemistry , nano , block (permutation group theory) , solvent , chemical engineering , composite material , chemistry , geometry , classical mechanics , organic chemistry , physics , mathematics , biology , engineering , genetics
Here, the cylinder to sphere transition property is reported in kinetically trapped block copolymer (BCP) nano‐objects made from polystyrene‐ block ‐poly( N ‐isopropylacrylamide) (PS‐ b ‐PNIPAM) in ethanol. The PS‐ b ‐PNIPAM BCPs are found to self‐assemble into hexagonally packed cylindrical morphology in bulk. When dispersing the bulk microphase‐separated BCP materials in selective solvent, nanocylinders stabilized by kinetically trapped PS cores were obtained. However, when the kinetic barrier is removed by external energy input, a morphology transition from cylinder to sphere occurred. The transition procedure could be accelerated by applying higher external energy, which could be realized by using higher temperatures as well as treating with ultrasonic. Additionally, lowering the kinetic barrier by using polymers with a shorter PS block also accelerates the morphology transition process.