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Effect of supercritical CO 2 on three‐dimensional colloid arrays of PS‐MA–EGDMA
Author(s) -
Chen Zhimin,
Xue Fengfeng,
Sun Guannan,
Chen Jiafu,
Xu Qun
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.32955
Subject(s) - materials science , supercritical fluid , coalescence (physics) , polymer , chemical engineering , colloid , dispersion polymerization , supercritical carbon dioxide , scanning electron microscope , ethylene glycol dimethacrylate , polymer chemistry , emulsion polymerization , polymerization , copolymer , methacrylic acid , composite material , chemistry , organic chemistry , physics , astrobiology , engineering
Using emulsifier‐free emulsion polymerization method, monodispersed crosslinked poly(styrene‐ co ‐methacrylic acid‐ co ‐ethylene glycol dimethacrylate) colloid microspheres were synthesized. The microspheres were treated in supercritical carbon dioxide (SCCO 2 ) after they have self‐assembled into ordered three‐dimensional (3D) colloid arrays. The CO 2 absorbed into the polymer microspheres enhances chain segments mobility and reduces the glass transition temperature ( T g ) of polymer, which induce the microspheres coalesce at the relatively low temperature. The coalescence degree of microspheres was studied by varying the experimental temperature, pressure, and exposure time in SCCO 2 . The results were shown by scanning electron microscopy (SEM). Further, the lattice spacing of the assembled 3D colloid microspheres was calculated from the SEM images. It was illustrated that the coalescence degree enhanced with the increase of CO 2 pressure; however, this tendency became weak when CO 2 pressure reached a certain value. Extending exposure time in SCCO 2 or elevating temperature can also increase coalescence degree, and the effect of temperature is more significant. It is believed that these results will make sense when the polymer microspheres are considered to be used as templates in SCCO 2 ; meanwhile, it raises a new method about tuning the final morphology of the stabilized colloidal crystals and porous materials via controlling the coalescence degree with the assistance of SCCO 2 . © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011