Twisted ABC Triblock Copolymer Cylinders with Segregated A and C Coronal Chains

• Published in: Macromolecules Vol. 41; no. 21; pp. 7993 - 7999
• Main Authors: Hu, Jiwen, Njikang, Gabriel, Liu, Guojun
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11.11.2008
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Solution and gel properties; Solvent effect; Terpolymer; Acrylic acid copolymer; Photochemical crosslinking; Experimental study; Butyl acrylate copolymer; Crosslinked copolymer; Hydrolysis; Monodispersed polymer; Alcohol copolymer; Triblock copolymer; Chemical modification; Mixed solvent; Molecular aggregation; Methacrylate copolymer; Alcoholic solution; Aqueous solution; Mechanism of action; Cinnamic derivative copolymer; Amphiphilic polymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma801626y

The formation of twisted cylinders with segregated A and C coronal chains from an ABC triblock copolymer in a block-selective solvent for the A and C blocks is reported. Such cylinders consisted of left- and right-handed helical sections (3D twisting) connected by wriggling (2D twisting) sections after aspiration on a solid substrate. The copolymer used was poly(glyceryl monomethacrylate)-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(tert-butyl acrylate) or PGMA-b-PCEMA-b-PtBA consisting of 310 PGMA units, 130 CEMA units, and 110 tBA units. Twisted cylinders were prepared from the dialysis of an aqueous solution of the triblock copolymer against methanol. In water, the copolymer formed core−shell−corona cylinders with the insoluble PtBA and PCEMA blocks making up the core and shell and the soluble PGMA block making up the corona. The cylinders with PCEMA cores twisted in water/methanol with high methanol contents, e.g., >90 vol%, probably to create more space to accommodate the segregated PGMA chains, which were longer, better solvated, and more crowded than the PtBA chains. Also investigated is the mechanism for the morphological transition from the core−shell−corona cylinders in water to the twisted cylinders in water/methanol.