Thu, 21 Aug 2008 06:51:41 BST CiteULike: rbgrubbs's Park http://www.citeulike.org/user/rbgrubbs/author/Park CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/rbgrubbs/article/2795493 <i>Macromolecules, Vol. 41, No. 6. (25 March 2008), pp. 2271-2277.</i><br /><br />Abstract: The phase behavior of ion-containing block copolymer membranes in equilibrium with humidified air is studied as a function of the relative humidity (RH) of the surrounding air, ion content of the copolymer, and temperature. Increasing RH at constant temperature results in both disorder-to-order and order-to-order transitions. In-situ small-angle neutron scattering experiments on the open block copolymer system, when combined with water uptake measurement, indicate that the disorder-to-order transition is driven by an increase in the partial molar entropy of the water molecules in the ordered phase relative to that in the disordered phase. This is in contrast to most systems wherein increasing entropy results in stabilization of the disordered phase. Humidity-Induced Phase Transitions in Ion-Containing Block Copolymer Membranes MJ Park AJ Nedoma PL Geissler NP Balsara A Jackson D Cookson doi:10.1021/ma702320t Macromolecules, Vol. 41, No. 6. (25 March 2008), pp. 2271-2277. 2008-05-13T15:43:01-00:00 2008 Macromolecules 41 6 2271 2277 bcp responsive structure http://www.citeulike.org/user/rbgrubbs/article/2795024 <i>Macromolecules, Vol. 41, No. 9. (13 May 2008), pp. 3181-3189.</i><br /><br />Abstract: We report that the amphiphilic rodcoilrod triblock copolymer with a coil attractive to the substrate surface self-organize into liquid crystalline monolayers or bilayers of a few nanometers thickness on the substrate surface. The copolymer investigated is a triblock copolymer, poly(n-hexyl isocyanate-b-2-vinylpyridine-b-n-hexyl isocyanate) (PHIC-b-P2VP-b-PHIC). Key processes of self-organization in the thin films, such as adsorption, desorption, diffusion, nematic and smectic ordering, and microphase separation, are tuned by exposing dip- or immersion-coated nanoscale films to the vapor of solvents which are rod (PHIC)-selective, coil (P2VP)-selective, or good to both blocks. Reorganization of the rodcoils in the nanofilms yielded various morphologies in the monolayer or bilayer, including unique long-range-ordered, smectic-on-nematic biphasic sheets. The results offer understanding on the complex morphological evolution in amphiphilic rodcoil block copolymers on the substrate surface. Self-Organization of an Amphiphilic Rod&#x2212;Coil&#x2212;Rod Block Copolymer into Liquid Crystalline, Substrate-Supported Monolayers and Bilayers Jee-Hyuk Kim Shahinur Rahman Jae-Suk Lee Ji-Woong Park doi:10.1021/ma702695a Macromolecules, Vol. 41, No. 9. (13 May 2008), pp. 3181-3189. 2008-05-13T13:39:37-00:00 2008 Macromolecules 41 9 3181 3189 rev triblock