Publications - 1990
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Neutron reflectivity and force balance studies of polymers adsorbed at the solid/solution interface
Terence Cosgrove, Jonathan S. Phipps, Robert M. Richardson, Michael L. Hair and David Guzonas
School of Chemistry, University of Bristol, Bristol, UK
Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) (1990), 31(2), 89-90
Abstract
The conformation of styrene-2-vinylpyridine block copolymers adsorbed on mica, silica, and quartz from soln. in various solvents was studied via neutron reflectivity. The results were interpreted in terms of various theor. models of the vol. fraction profiles of the adsorbed layer.
Volume-fraction profiles of adsorbed polymers [Erratum to document cited in CA113(4):24889z]
Terence Cosgrove
School of Chemistry, University of Bristol, Bristol, UK
J. Chem. Soc., Faraday Trans. (1990), 86(23), 3973
Abstract
Errors in Figures 7-11, 13, and 14 have been cor. The errors were not reflected in the abstr. or the index entries.
NMR diffusion measurements using refocused three-pulse stimulated echoes
Lee Griffiths, Rob Horton and Terence Cosgrove
Res. Technol. Dep., ICI Chem. Polym., Heath/Runcorn/Cheshire, UK
J. Magn. Reson. (1990), 90(2), 254-63
Abstract
A modification is proposed to the three-pulse stimulated-echo pulse sequence for measuring high-resoln. self-diffusion coeffs., which substantially minimizes phase distortions and other spectral artifacts. The new pulse sequence yields accurate self-diffusion coeffs.
The effects of solvency on the structure of an adsorbed polymer layer and dispersion stability
Terence Cosgrove, Trevor L. Crowley, Keith Ryan and John R.P. Webster
School of Chemistry, University of Bristol, Bristol, UK
Colloids Surf. (1990), 51 255-69
Abstract
Small-angle neutron scattering and photon correlation spectroscopy were used to det. the vol. fraction profiles, adsorbed amts. and hydrodynamic thickness of vinyl alc.-vinyl acetate copolymer and poly(ethylene oxide) adsorbed on polystyrene latex from water. The effects of solvency on the structure of the adsorbed layer and the stability of the dispersions were investigated by varying temp. in the presence of electrolyte. The results show that the thickness of the layer contracts on approach to flocculation and that the vol. fraction of segments near the interface increases together with a concomitant increase in the adsorbed amt. The profiles are used to calc. the steric barrier due to interpenetration and the results are discussed in terms of dispersion stability.
Chemisorption of linear and cyclic polymethylsiloxanes on alumina studied by Fourier-transform infrared spectroscopy
Terence Cosgrove, Clive A. Prestidge and Brian Vincent
School of Chemistry, University of Bristol, Bristol, UK
J. Chem. Soc., Faraday Trans. (1990), 86(9), 1377-82
Abstract
Cyclic and linear versions of poly(methylsiloxane) (I) were adsorbed on Al2O3 from soln. in tetrachloromethane. The Si-H moieties undergo a condensation reaction with hydroxyl groups assocd. with the alumina surface, with the elimination of mol. H, and become chem. bound to the surface. The extent of this chemisorption depends on the initial soln. concn. and the polymer type; the process of chemisorption is, however, preceded by phys. sorption. The rate and extent of these polymer-surface interactions were monitored by (FTIR) spectroscopy. The results show marked differences in the behavior of cyclic and linear mols. and are in qual. agreement with calcns. based on the equil. mean-field theory of J. M. H. M. Scheutjens and G. J. Fleer. Sequential adsorption studies, however, carried out after chemisorption has occurred indicate irreversible adsorption. Some adsorption results are also presented for AB block copolymers of I and poly(dimethylsiloxane).
Volume-fraction profiles of adsorbed polymers
Terence Cosgrove
School of Chemistry, University of Bristol, Bristol, UK
J. Chem. Soc., Faraday Trans. (1990), 86(9), 1323-32
Abstract
The role of neutron scattering and NMR in the title study is reviewed and discussed. Although the form of the vol.-fraction profile of polymer segments normal to the interface was predicted in detail from theory, few exptl. methods can probe more than the first or second moments of this distribution. The results of these studies are compared with various theor. models. The picture of the adsorbed layer that emerges is one that shows a strong dependence on the structure of the polymer, and the interactions between polymer segments, the interface and solvent(s).
Monte Carlo simulations of adsorbed random copolymers
Terence Cosgrove, Nigel A. Finch and John R.P. Webster
School of Chemistry, University of Bristol, Bristol, UK
Macromolecules (1990), 23(13), 3353-7
Abstract
A Monte Carlo method was described for simulating the conformations of random copolymers at the solid/solvent interface. The effects of solvency, preferential adsorption, chain length, and coverage were considered. The effects of varying the point of attachment, the chain compn., and the cell boundary were discussed. Vol. fraction profiles normal and parallel to the surface were calcd. and comparisons were made with exptl. data from small-angle neutron scattering.
NMR and neutron-scattering studies on poly(ethylene oxide) terminally attached at the polystyrene/water interface
Terence Cosgrove and Keith Ryan
School of Chemistry, University of Bristol, Bristol, UK
Langmuir (1990), 6(1), 136-42
Abstract
Small-angle neutron scattering (SANS) and NMR were used to investigate the structure of terminally attached polymers at the polystyrene latex/water interface. In particular, vol. fraction profiles obtained by SANS and by the Scheutjens-Fleer mean-field theory of polymer adsorption were used to calc. spin-spin relaxation functions for the adsorbed layer with different adsorbed polymer coverages and chain lengths. These were compared to the exptl. detd. relaxation functions obtained by using NMR. There was a good qual. agreement with the three approaches.
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