Publications - 1991
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Reply to comment by J. Kaerger and H. Jobic on "The diffusion of benzene in high silica zeolite ZSM 5 studied by PFGNMR and QUENS"
T. Cosgrove, M. Morgan and R.M. Richardson
School of Chemistry, University of Bristol, Bristol, UK
Colloids Surf. (1991), 58(1-2), 207-9
Abstract
A polemic is given in reply to J. Kaerger and H. Jobic (ibid. 1991, 58 (1-2), 203-5).
Studies of cyclic and linear poly(dimethylsiloxanes): 30. Adsorption studies on silica in solution
A. Patel, T. Cosgrove and J.A. Semlyen
Dep. Chem., Univ. York, Heslington/York, UK
Polymer (1991), 32(7), 1313-17
Abstract
The adsorbed amts. of cyclic and linear di-Me siloxane fractions of heterogeneity indexes Mw/Mn ~ 1.05 on silica are investigated by FTIR. At low molar masses the adsorption of cyclic polymer is greater than that of the corresponding linear polymer, but at high molar masses the reverse behavior is found. This is in agreement with the theor. predictions of van Lent, Scheutjens, and Cosgrove. Adsorption of the polymers is investigated in 2 different solvents, and adsorption is greater from hexane than from CCl4 for both linear and cyclic polymers.
Polymer adsorption and desorption studies via proton NMR relaxation of the solvent
G.P. Van der Beek, M.A. Cohen Stuart and T. Cosgrove
Lab. Phys. Colloid Chem., Agric. Univ., Wageningen, Netherlands
Langmuir (1991), 7(2), 327-34
Abstract
Proton NMR relaxation measurements of the solvent in silica dispersions were carried out as a function of polymer coverage, soln. pH, and added displacer. The solvent spin-lattice relaxation rate was enhanced as a result of polymer adsorption and, with proper calibration, this enhancement was used to obtain the adsorbed amt. in trains. The results were consistent with bound fraction ests. obtained from the Scheutjens-Fleer theory of polymer adsorption and also with recent results on the hydrodynamic thickness of adsorbed polymer layers. Besides information about the conformation of adsorbed polymers, the effective polymer adsorption energy can also be detd. by this NMR technique.
Neutron reflectivity studies of polymers adsorbed on mica from solution
Terence Cosgrove, Timothy G. Heath, Jonathan S. Phipps and Robert M. Richardson
School of Chemistry, University of Bristol, Bristol, UK
Macromolecules (1991), 24(1), 94-8
Abstract
Neutron reflectivity is used to study the conformation of either styrene-2-vinylpyridine block copolymer (I) or polystyrene (II) adsorbed on mica from soln. The reflectivity profiles are fitted to theor. models of the vol. fraction profiles of the adsorbed layer. For II, the best fits are obtained with profiles having an exponential decay, although the theor. profiles are quant. in error; for I, profiles with a max. or parabolic shape give the best fits. Phys.-adsorbed polymers have profiles that decay monotonically; polymers with terminally-attached tails precluded from returning to the interface have profiles that have a max. or are parabolic.
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