Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5188813 | Polymer | 2006 | 8 Pages |
Abstract
The small-angle neutron scattering investigation was carried out on semi-dilute aqueous solutions of block and gradient copolymers comprising pEOVE and pMOVE, pEOVE300-block-pMOVE300 (Block) and p(EOVE-grad-MOVE)600 (Grad). Here, pEOVE and pMOVE denote poly(2-ethoxyethyl vinyl ether) and poly(2-methoxyethyl vinyl ether), respectively, and the numbers indicate the degrees of polymerization. The monomer composition in the Grad had a gradient along the polymer chain. For 20.0Â wt% solutions, a microphase-separated structure and physical gelation were observed both in Block and in Grad systems. In the case of the Grad system, a gradual microphase separation took place as a function of temperature via a micellization with a small radius of core, characterized by the “reel-in” process, i.e., a winding of polymer chains to the core of a micelle because of the gradient composition. On the other hand, the Block system underwent a stepwise transition with respect to temperature. The relationship between microphase separation and the rheological behavior is explained from the viewpoint of microscopic structure.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Satoshi Okabe, Ken-ichi Seno, Shokyoku Kanaoka, Sadahito Aoshima, Mitsuhiro Shibayama,