Mei-Chan Ho, Ching-Hsun Chao, Chun-Hua Chen
Mar 21, 2012
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Influential Citations
9
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Journal
Macromolecules
Abstract
Polycondensation of 4-bis[2-(1-methylpyrrol-2-yl)vinyl]-2,5-didodecyloxybenzene and squaric acid yielded the polysquaraine SQ with two isomeric subunits—1,3-addition (zwitterionic) and 1,2-addition (diketonic) moieties—in the main chain structure. The former featured a C–O/C═O infrared (IR) absorption frequency at 1622 cm–1; the latter, a C═O signal at 1716 cm–1. Traditional synthesis yielded SQ as a powder with metallic luster that could not be cast as a polymer film from solution. When the ionic liquid [Oct3NMe][TfO] (IL) was present in the cosolvent of BuOH and benzene (1:3), however, the resulting SQIx polymers (x = 0.01–5 wt %) did not precipitate from solution, making it possible to cast continuous free-standing films with a large area (>1 × 1 cm2). A greater content of IL in the solution favored the formation of the 1,3-addition zwitterionic subunits in the SQIx polymer main chains, thereby changing the physical and optical properties of the polysquaraine, as evidenced in IR and optical absorption ...