Macroscopic modelling of the surface tension of polymer-surfactant systems by Bell, C, Breward, C, Howell, P, Penfold, J, Thomas, R

“…In this paper we shouw how an existing model based on the law of mass action can be extended to model the surface tension of weakly-interacting systems, and we also extend it further to produce a model for the surface tension of strongly interacting systems. …”

Macroscopic modeling of the surface tension of polymer-surfactant systems. by Bell, C, Breward, C, Howell, P, Penfold, J, Thomas, R

“…In this paper we show how an existing model based on the law of mass action can be extended to model the surface tension of weakly interacting systems, and we also extend it further to produce a model for the surface tension of strongly interacting systems. …”

A theoretical analysis of the surface tension profiles of strongly interacting polymer-surfactant systems. by Bell, C, Breward, C, Howell, P, Penfold, J, Thomas, R

“…Measurements of the surface tension of static polymer-surfactant mixtures as the concentrations of polymer and surfactant are varied produce interesting and surprising profiles. …”

Limitations in the use of surface tension and the Gibbs equation to determine surface excesses of cationic surfactants. by Li, P, Thomas, R, Penfold, J

“…Neutron reflection (NR) and surface tension (ST) are used to show that there are serious limitations in applying the Gibbs equation accurately to ST data of cationic surfactants to obtain the limiting surface excess, Γ(CMC), at the critical micelle concentration (CMC). …”

Investigation of mixing in binary surfactant solutions by surface tension and neutron reflection: Anionic/nonionic and zwitterionic/nonionic mixtures by Hines, J, Thomas, R, Garrett, P, Rennie, G, Penfold, J

“…Surface tension and neutron reflection measurements have been used to study the surface composition of aqueous solutions of mixtures of sodium dodecyl sulfate (SDS) and n-dodecyl-β-D-maltoside (C12maltoside) and C12maltoside and n-dodecyl-N,n′-dimethylamino betaine (C12betaine). …”

Investigation of mixing in binary surfactant solutions by surface tension and neutron reflection: Strongly interacting anionic/zwitterionic mixtures by Hines, J, Thomas, R, Garrett, P, Rennie, G, Penfold, J

“…Application of the pseudo-phase separation model to surface tension data was used to show that the interaction parameter βσ in the surface layer is similarly large and negative. …”

STRUCTURE AND COMPOSITION OF DODECANE LAYERS SPREAD ON AQUEOUS-SOLUTIONS OF TETRADECYLTRIMETHYLAMMONIUM BROMIDE - NEUTRON REFLECTION AND SURFACE-TENSION MEASUREMENTS by Lu, J, Thomas, R, Aveyard, R, Binks, B, Cooper, P, Fletcher, P, Sokolowski, A, Penfold, J

“…Neutron reflection and surface tension measurements have been used to study the composition and structure of a mixed (alkane + surfactant) monolayer at the air-water surface, formed either by adsorption from vapor or by spreading dodecane from small lenses placed on the surface of an aqueous solution of tetradecyltrimethylammonium bromide (C14TAB). …”

COMPARISON OF NEUTRON REFLECTION AND SURFACE-TENSION MEASUREMENTS OF THE SURFACE EXCESS OF TETRADECYLTRIMETHYLAMMONIUM BROMIDE LAYERS AT THE AIR-WATER-INTERFACE by Simister, E, Thomas, R, Penfold, J, Aveyard, R, Binks, B, Cooper, P, Fletcher, P, Lu, J, Sokolowski, A

“…The fourth species showed a slight surface tension minimum but was otherwise similar. The close similarity of the surface tension curves indicated that the surface properties of C14TAB are independent of deuteration, a result of importance for the interpretation of neutron reflectivity. …”

ADSORPTION OF DODECYL-SULFATE SURFACTANTS WITH MONOVALENT METAL COUNTERIONS AT THE AIR-WATER-INTERFACE STUDIED BY NEUTRON REFLECTION AND SURFACE-TENSION by Lu, J, Marrocco, A, Su, T, Thomas, R, Penfold, J

“…Neutron reflection and surface tension have been used to study the adsorption at the air-water interface of the dodecyl sulfates of the alkali metals (MDS). …”

Properties of aqueous solutions of triblock copolymers of ethylene oxide and propylene oxide and their mixtures with surfactants studied by surface tension and neutron reflection by Viera, J, Josélio, Vieira

“…The surface tension curves for the copolymers show two breaks similar to those published for Pluronic 3 surfactants (commercially available EPE copolymers). …”

Behavior of nonionic water soluble homopolymers at the air/water interface: Neutron reflectivity and surface tension results for poly(vinyl methyl ether) by An, S, Thomas, R, Forder, C, Billingham, N, Armes, S, Penfold, J

“…However, an upturn in the surface tension at low concentrations, which has been observed in several related systems, is attributed to two possible contributions. …”

pH sensitive adsorption of polypeptide/sodium dodecyl sulfate mixtures. by Penfold, J, Tucker, I, Thomas, R, Taylor, D, Zhang, X

“…The surface tension variation with surfactant concentration is complex, and between the critical aggregation concentration and critical micellar concentration there is a marked increase in the surface tension. …”

Organization of polymer-surfactant mixtures at the air-water interface: Poly(dimethyldiallylammonium chloride), sodium dodecyl sulfate, and hexaethylene glycol monododecyl ether by Staples, E, Tucker, I, Penfold, J, Warren, N, Thomas, R

“…The variation of surface tension with surfactant concentration shows a similar complex behavior to that observed and previously reported for SDS/poly-dmdaac. …”

Surface behavior, aggregation and phase separation of aqueous mixtures of dodecyl trimethylammonium bromide and sodium oligoarene sulfonates: the transition to polyelectrolyte/surf... by Jiang, L, Huang, J, Bahramian, A, Li, P, Thomas, R, Penfold, J

“…These systems exhibit a single critical micelle concentration (CMC) at which the surface tension reaches the usual plateau. This is contrary to a recent report which suggests that the onset of the surface tension plateau does not coincide with the CMC. …”

Surface behavior, aggregation and phase separation of aqueous mixtures of dodecyl trimethylammonium bromide and sodium oligoarene sulfonates: The transition to polyelectrolyte/surf... by Jiang, L, Huang, J, Bahramian, A, Li, P, Thomas, R, Penfold, J

“…These systems exhibit a single critical micelle concentration (CMC) at which the surface tension reaches the usual plateau. This is contrary to a recent report which suggests that the onset of the surface tension plateau does not coincide with the CMC. …”

Organization of polymer-surfactant mixtures at the air-water interface: Sodium dodecyl sulfate and poly(dimethyldiallylammonium chloride) by Staples, E, Tucker, I, Penfold, J, Warren, N, Thomas, R, Taylor, D

“…The neutron reflectivity measurements show that this change in surface tension is associated with changes in the amount of SDS anal polymer at the interface. …”

Apparent anomalies in surface excesses determined from neutron reflection and the Gibbs equation in anionic surfactants with particular reference to perfluorooctanoates at the air/... by An, S, Lu, JR, Thomas, R, Penfold, J

“…The surface tension and neutron reflectivity of several perfluorooctanoic acid salts with monovalent metal cations have been investigated over a wide range of surfactant, counterion, and co-ion concentrations. …”

Neutron reflectometry of quaternary gemini surfactants as a function of alkyl chain length: anomalies arising from ion association and premicellar aggregation. by Li, P, Dong, C, Thomas, R, Penfold, J, Wang, Y

“…The structures of the surface layers, which were determined by neutron reflectometry, indicate that the anomalous behavior of the surface tension and area are probably caused by poor packing of the gemini side chains between adjacent molecules. …”

Adsorption of polymer/surfactant mixtures at the air-water interface: Ethoxylated poly(ethyleneimine) and sodium dodecyl sulfate by Penfold, J, Taylor, D, Thomas, R, Tucker, I, Thompson, L

“…The adsorption of the polymer/surfactant mixture of ethoxylated poly(ethyleneimine) (PEI) and sodium dodecyl sulfate (SDS) at the air-water interface has been studied by specular neutron reflectivity and surface tension. PEI is a strong polyelectrolyte at low pH and behaves like a neutral polymer at high pH. …”

Adsorption of oppositely charged polyelectrolyte/surfactant mixtures. Neutron reflection from alkyl trimethylammonium bromides and sodium poly(styrenesulfonate) at the air/water in... by Taylor, D, Thomas, R, Li, P, Penfold, J

“…The surface tension and neutron reflection results were explained in terms of a model in which there were three kinds of polymer/surfactant complex.…”