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pH-responsive aqueous/LC interfaces using SGLCP-b-polyacrylic acid block copolymers

Lee, Dong-Yul and Seo, Jung-Min and Khan, Waliullah and Kornfield, Julia A. and Kurji, Zuleikha and Park, Soo-Young (2010) pH-responsive aqueous/LC interfaces using SGLCP-b-polyacrylic acid block copolymers. Soft Matter, 6 (9). pp. 1964-1970. ISSN 1744-683X.

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Block copolymers that combine a side-group liquid crystalline polymer (SGLCP) block and a pH-responsivehydrophilic block, poly(acrylic acid) (PAA), are shown to confer pH-dependent anchoring of the director orientation at the aqueous/LC interface. The SGLCP block, poly(4-cyanobiphenyl-4-oxyundecylacrylate), was chosen based on its ability to influence the director field of the 5CB (4-cyano-4'-pentylbiphenyl). At low pH the PAA block collapses and the inherent, planar alignment tendency of 5CB at a water interface prevails. As pH increases, the polyelectrolyte block becomes increasingly charged and expands, producing a change to homeotropic anchoring. The change in anchoring occurs as quickly as the buffer can be changed (within ~2 s) and is reversible, with a response that is repeatable over as many cycles as were tested (approximately 20 cycles). The polymer-mediated anchoring persists for 6 days, indicating that the SGLCP block secures the self-assembled layer on the 5CB, even under conditions that cause repulsive interactions among the PAA blocks. Thus, SGLCP blocks can translate conformational changes of a responsive hydrophilic block into rapid, reversible changes in the director field

Item Type:Article
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Kornfield, Julia A.0000-0001-6746-8634
Additional Information:© 2010 The Royal Society of Chemistry. Received 15th December 2009, Accepted 22nd February 2010. First published as an Advance Article on the web 26th March 2010.
Issue or Number:9
Record Number:CaltechAUTHORS:20100517-153103244
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18331
Deposited By: Tony Diaz
Deposited On:24 May 2010 02:24
Last Modified:03 Oct 2019 01:41

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