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Transient instability upon temperature quench in weakly ordered block copolymers

Qi, Shuyan and Wang, Zhen-Gang (1999) Transient instability upon temperature quench in weakly ordered block copolymers. Journal of Chemical Physics, 111 (23). pp. 10681-10688. ISSN 0021-9606. http://resolver.caltech.edu/CaltechAUTHORS:QISjcp99

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Abstract

We report a novel transient instability upon temperature quench in weakly ordered block copolymer microphases possessing a soft direction or directions, such as the lamellar and hexagonal cylinder (HEX) phases. We show that reequilibration of the order parameter is accompanied by transient long wavelength undulation of the layers or cylinders—with an initial wavelength that depends on the depth of the temperature quench—that eventually disappears as the structure reaches its equilibrium at the new temperature. Such undulation leads to a transient transverse broadening of the scattering peaks near the Bragg positions. We argue that this instability might be responsible for the experimentally observed unusual ordering dynamics of the HEX phase of a diblock copolymer after quenching from the disordered state.


Item Type:Article
Additional Information:©1999 American Institute of Physics. (Received 22 July 1999; accepted 17 September 1999) We thank Professors N.P. Balsara, M. Muthukumar, and M. Cross for helpful discussions. We particularly thank Professor N.P. Balsara for explaining his experimental findings in Ref. 34 to us which in large part provide the impetus for our work. Financial support from the National Science Foundation DMR-9531914), the Camille and Henry Dreyfus Foundation (TC-96-063), the Alfred P. Sloan Foundation (BR-3508), and the Department of Energy (BES, through Professor A. K. Chakraborty at UC Berkeley) is gratefully acknowledged.
Subject Keywords:COPOLYMERS; QUENCH HARDENING; ORDER PARAMETERS; PHASE STABILITY; polymer blends; quenching (thermal)
Record Number:CaltechAUTHORS:QISjcp99
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:QISjcp99
Alternative URL:http://dx.doi.org/10.1063/1.480422
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8774
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:15 Sep 2007
Last Modified:26 Dec 2012 09:42

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