Terence Cosgrove

Terence Cosgrove
University of Bristol | UB · School of Chemistry

BSc MSc PhD DSc

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276
Publications
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Publications

Publications (276)
Preprint
Full-text available
The adsorption of copolymers of polystyrene and hydrogenated polyisoprene block copolymers adsorbed from cyclohexane onto carbon black has been investigated. The adsorption of the copolymers was found strongly dependent on copolymer composition. The conformation of the adsorbed polymer is largely determined by the surface-copolymer interaction, esp...
Article
The selection of appropriate solvents into which inorganic and organic sub-micron particles can be dispersed is important for product manufacturability and performance. Molecular-level interactions determine solvent suitability but are difficult to measure; existing experimental approaches require slow/expensive tests of dispersion stability. Solve...
Article
Full-text available
V.Rodin, T.Cosgrove. (2016) Nuclear Magnetic Resonance Study of Water-Polymer Interactions and Self-Diffusion of Water in Polymer Films.// Open Access Library Journal: Chemistry and Materials Science, Fundamentals of Materials Sciences. Vol.3, Issue 10, pp.1-17. doi: 10.4236/oalib.1103018. http://www.scirp.org/journal/PaperInformation.aspx?PaperID=...
Article
Full-text available
Aqueous dispersions of single-walled carbon nanotubes are often made using sodium dodecylsulfate (SDS), which adsorbs to the nanotube surface to stabilise them. Despite SDS being commonly used with single-walled carbon nanotubes, there is no consensus on the structure of the adsorbed layer. Small-angle neutron and X-ray scattering results reported...
Article
A series of dumbbell shape nanocomposite materials of polydimethylsiloxanes (PDMS) and polyhedral oligomeric silsesquioxanes (POSS) was synthesized through hydrosilylation reactions of allyl- and vinyl-POSS and hydride-terminated PDMS. The chemical structures of the dumbbell shaped materials, so called POSS-PDMS-POSS triblocks, were characterized b...
Article
Solvent relaxation NMR has been used to estimate the surface areas and wettability of various types of nanostructured carbon materials in a range of solvents including water, ethanol, and tetrahydrofuran. We illustrate the application of the technique through several short case studies using samples including nanocarbon blacks, graphene oxide, nano...
Article
The interactions between the strong polyelectrolyte sodium poly(styrene sulfonate), NaPSS, and the neutral polymer poly(vinyl pyrrolidone), PVP, were investigated in bulk and at the silica/solution interface using a combination of diffusion NMR, SANS, solvent relaxation NMR and ellipsometry. We show for the first time that complex formation occurs...
Article
Aqueous single-walled carbon nanotube dispersions are often made using polymers from the Pluronic family of amphiphilic block copolymers, however relatively few studies have been made using small-angle neutron scattering techniques to discover the mechanism by which they act. SANS results reported here show that a relatively simple core-shell cylin...
Article
Methacrylate-terminated poly(dimethylsiloxane)s in both linear and star architectures have been produced through a time-efficient 1 pot, 2 stage reaction which involved hydrosilylation of small molecule silanes with allyl methacrylate and subsequent equilibration of the product with octamethylcyclotetrasiloxane (D4) in the presence of an acid catal...
Article
Understanding the flow of particles through accessible paths in timber is important to optimising the timber preservation process. In this paper, we identify inconsistencies between the previously established flow paths in timber for simple liquids, and those for particulate systems. We show that the flow paths of nanofluids are through the rays of...
Patent
Full-text available
The present invention provides a method for making a composition comprising an amphiphilic polymeric material which comprises a straight or branched chain carbon-carbon backbone and a multiplicity of side chains attached to the backbone; wherein in the method, backbone precursors comprising acylating groups are mixed with side chain precursors whic...
Article
Optical flow cell reflectometry was used to study the adsorption of poly(vinylpyrrolidone) (PVP) to a silica surface and the subsequent surfactant adsorption and polymer desorption upon exposure to the anionic surfactant sodium dodecyl sulfate (SDS). We have studied these effects as a function of pH and surfactant concentration, but also for two di...
Article
Novel amphiphilic graft copolymers composed of a polyisoprene (PIP) backbone with Pluronic side chains, polyisoprene-g-Pluronic, have been synthesized using a "graft onto" technique. Small-angle neutron scattering (SANS) has been used to characterize the conformation of the P123 and P103 Pluronic graft copolymers in selective solvents such as ethan...
Article
The weak polyelectrolyte sodium polyacrylate, NaPA, and the neutral poly(vinyl pyrrolidone), PVP, were combined and the effects of complexation both in solution and at the nanoparticle interface were studied under basic pH conditions. Using a combination of SANS and PCS, we demonstrate that attractive interpolymer interactions occur between PVP and...
Article
Full-text available
Reports as early as 1974[1] have indicated that polymer nanocomposites(PNCs) can exhibit viscosities that decrease with particle addition counter to the classical behavior for filled systems originally described by Einstein[2]. Schmidt et. al.[3] previously reported that PNC's prepared from trimethylsiloxy-treated polysilicate nanoparticles of 0.75...
Article
The competition between poly(vinyl pyrrolidone) and poly(ethylene oxide) for adsorption at the silica surface was studied by solvent relaxation nuclear magnetic resonance and small-angle neutron scattering. The additive nature of the NMR relaxation rate enhancement was used to observe changes in the train layer when the two polymers were in direct...
Article
Solvent relaxation nuclear magnetic resonance has been widely used to study the interactions of polymers and surfactants with nanoparticles, an important area of research for use in a range of industrial formulations, especially with regards to competition effects between components. The ability of the solvent relaxation technique to distinguish be...
Article
A new interpretation for the mechanism associated with the spontaneous threading of α-CD, onto a PEG chain followed by the supramolecular hydrogel formation, is described in this article. Beyond a specific stoichiometry, the complexation of α-CD and PEG results in the formation of a two-phase system. Beyond the phase separation, for PEG with molecu...
Article
We have developed a unique surface force type apparatus that allows direct measurements of the structure of a polymer layer under a confining pressure using neutron reflection. We have used this device to study the structure and the mechanical properties of a water swollen poly(styrenesulfonic acid) (PSSA) and poly(allylamine) PAH polyelectrolyte m...
Article
Full-text available
Binary mixtures of colloidal particles of sufficiently different sizes or shapes tend to demix at high concentration. Already at low concentration, excluded volume interactions between the two species give rise to structuring effects. Here, a new theoretical description is proposed of the structure of colloidal sphere-plate mixtures, based on a den...
Article
Full-text available
The phase behaviour of colloidal dispersions is interesting for fundamental reasons and for technological applications such as photonic crystals and electronic paper. Sedimentation, which in everyday life is relevant from blood analysis to the shelf life of paint, is a means to determine phase boundaries by observing distinct layers in samples that...
Article
The competitive adsorption of poly(vinyl pyrrolidone) onto silica and alumina-modified silica particles was studied using solvent relaxation nuclear magnetic resonance. The additive nature of the measured relaxation rate enabled predictions to be made of the relaxation rate in different polymer adsorption scenarios. Preferential adsorption of the p...
Article
A unique surface force type apparatus that allows the investigation of a confined thin film using neutron reflection is described. The central feature of the setup consists of a solid substrate (silicon) and a flexible polymer membrane (Melinex(®)). We show that inflation of the membrane against the solid surface provides close and even contact bet...
Article
Structural changes in the micellization of Pluronics P103 and P123, as a function of temperature, cosolvent (ethanol, 10 v/v %), and the addition of the hydrophobic drug flurbiprofen, were investigated by SANS and tensiometry. Addition of ethanol increases the critical micellization concentration of the Pluronics (making the polymer more soluble),...
Article
Full-text available
The micellization of Pluronic triblock copolymers (P103, P123, and L43) in the presence of flurbiprofen at different pH was studied by small-angle neutron scattering (SANS), pulsed-field gradient stimulated-echo nuclear magnetic resonance (PFGSE-NMR), and surface tension measurements. Addition of flurbiprofen to the Pluronic at low pH leads to an i...
Article
The effects of a nonionic alcohol ethoxylate surfactant, C(13)E(7), on the interactions between PVP and SDS both in the bulk and at the silica nanoparticle interface are studied by photon correlation spectroscopy, solvent relaxation NMR, SANS, and optical reflectometry. Our results confirmed that, in the absence of SDS, C(13)E(7) and PVP are nonint...
Article
The surfactant-mediated desorption of adsorbed poly(vinylpyrrolidone), PVP, from anionic silica surfaces by sodium dodecyl sulfate, SDS, was observed. While photon correlation spectroscopy shows that the size of the polymer-surfactant-particle ensemble grows with added SDS, a reduction in the near-surface polymer concentration is measured by solven...
Article
Pulsed-field gradient stimulated-echo nuclear magnetic resonance (NMR) and surface tension measurements have been used to study the effect of drug addition on the micellization behavior of pluronic triblock copolymers (P103, P123, and L43). The addition of 0.6 wt% flurbiprofen to Pluronic P123 and P103 solutions reduced their cmc and promoted micel...
Article
Full-text available
In addition to containing spherical pigment particles, coatings usually contain plate-like clay particles. It is thought that these improve the opacity of the paint film by providing an efficient spacing of the pigment particles. This observation is counterintuitive, as suspensions of particles of different shapes and sizes tend to phase separate o...
Article
Dilute aqueous solutions of d-PEO and PSSNa mixtures were studied by (2)H NMR spectroscopy and small-angle neutron scattering (SANS). The interactions between d-PEO and PSSNa were found to be negligible both in the presence and absence of NaCl. At very dilute concentration (0.7 mg mL(-1)), d-PEO chains were still found to be slightly collapsed at a...
Article
Introducing hard spherical polysilicate nanoparticles up to 0.30 volume fraction into narrow molecular weight (M) fractions of poly(dimethylsiloxane) (PDMS) that spanned its unentangled and entangled polymer chain regimes produced transparent and colorless polymer nanocomposites (PNCs) with zero-shear-rate viscosities η0 either greater or less than...
Chapter
A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended as an introduction into this very vibrant and div...
Article
The zero-shear-rate viscosity η0 of polymer−nanocomposites (PNCs) derived from entangled poly(dimethylsiloxane)s and rigid polysilicate nanoparticles were investigated as a function of molecular size and concentration. Narrow molecular weight fractions of polymer and nanoparticle were obtained by supercritical fluid extraction. Molecular weight pro...
Article
The effect of two model adjuvants (benzyl benzoate and benzyl alcohol) on the structure and dynamics of three Pluronic triblock copolymers (P85, P105 and F127) was studied using small-angle neutron scattering and pulsed-field gradient NMR. The two adjuvants studied have different aqueous solubilities. It was found that both adjuvants promoted the m...
Article
The rates of catalytic oxidative decontamination of the chemical warfare agent (CWA) sulfur mustard (HD, bis(2-chlororethyl) sulfide) and a range (chloroethyl) sulfide simulants of variable lipophilicity have been examined using a hydrogen peroxide-based microemulsion system. SANS (small-angle neutron scattering), SAXS (small-angle X-ray scattering...
Article
The effect of drug addition and pH variation on Pluronic copolymer solutions has been investigated using pulsed-field gradient (PFG) NMR. Addition of ibuprofen to Pluronic P104 in solution reduced the overall pH from 7.5 to 4.5, as well as promoting micellization; a substantial increase in the hydrodynamic radius of the micelles, from 57.7 to 102.3...
Article
The influence of hydroxypropyl guar (HPG), with and without boric acid, on dodecyltrimethyl ammonium bromide (DTAB) micellization was characterized by surface tension measurements, isothermal titration calorimetry, and small-angle neutron scattering. Although HPG is a nonionic water-soluble polymer, borate ions form weak bonds with HPG, transformin...
Article
The composite chitosan/gelatin solutions and films formed from these solutions were studied by rheological measurements, SANS and tensile tests. The relationship between the inter-molecule interactions with microstructure, rheological behaviour of a solution and eventually the mechanical performance of formed films was established. It was found tha...
Article
Small-angle neutron scattering and pulsed-field gradient stimulated-echo nuclear magnetic resonance (NMR) have been used to study the structural characteristics of aqueous Pluronic solutions. In particular, changes in the micellar structure upon addition of ibuprofen to the solutions and altering the temperature have been investigated. Increases in...
Chapter
IntroductionPolymerisationCopolymersPolymer physical propertiesPolymer UsesTheoretical models of polymer structureMeasuring polymer molecular weightPolymer solutionsReferences
Chapter
Colloidal systems are important across a range of industries, such as the food, pharmaceutical, agrochemical, cosmetics, polymer, paint and oil industries, and form the basis of a wide range of products (eg cosmetics & toiletries, processed foodstuffs and photographic film). A detailed understanding of their formation, control and application is re...
Article
The effect of a polyelectrolyte, poly(styrenesulfonate sodium) (PSS), on poly(ethylene oxide) (PEO) adsorption on the polystyrene latex (PSL) particle/water interface at different sodium chloride (NaCl) concentrations has been investigated by small-angle neutron scattering (SANS). Our study shows that in the absence of NaCl or with a low NaCl conce...
Article
The interaction between poly(ethylene oxide) (PEO) chains grafted onto polystyrene latex particles and alpha-, beta-, and gamma-cyclodextrins (CD) was studied by small-angle neutron scattering. The particles were contrast-matched to the solvent in order that only the scattering from the polymer layers was detected. The signal from the layers was fi...
Article
Kaolin particles were surface-treated with isobutyltrimethoxysilane (IBTMS), hydrogenated tallow (HT), and a polyisobutyl chain-based stabilizer (SAP) to make composites with polydimethylsiloxane (PDMS). IBTMS did not cover the strong acid sites on the kaolin surface and as a result a cross-linking reaction occurred for silanol-terminated PDMS. The...
Article
Full-text available
The direct manipulation by atomic force microscopy (AFM) of individual macrocycles within a rotaxane offers a potential route to a new sequencing tool for complex macromolecules such as polysaccharides, glycoproteins and nucleic acids. In this paper we demonstrate for the first time that a sliding contact made between a macrocycle, α-cyclodextrin,...
Article
Adsorbed polymer and polyelectrolyte layers on colloidal silica nanoparticles have been studied in the presence of various salts and surfactants using photon correlation spectroscopy and solvent relaxation NMR. Poly(ethylene oxide) (PEO; molar mass 103.6 kg mol (-1)) adsorbed with a relatively high affinity and gave a layer thickness of 4.2 +/- 0.2...
Article
Fourier transform relaxation NMR has been used to study how the mobility of poly(ethylene oxide) is affected by its adsorption onto colloidal silica particles of various sizes. Novel results have been obtained which illustrate the unexploited potential of this method for the study of interfacial species in complex systems. The results quantify how...
Article
Blends of chitosan and poly(vinyl pyrrolidone) (PVP) have a high potential for use in various biomedical applications and in advanced drug-delivery systems. Recently, the physical and chemical properties of these blends have been extensively characterized. However, the molecular interaction between these two polymers is not fully understood. In thi...
Article
Poly(ethylene oxide) (PEO) adsorption on colloidal silica particles was studied by small-angle neutron scattering under the core-contrast-matching condition. The volume fraction profile of the adsorbed layer was derived by modeling the average layer scattering term. It was found that, with increasing colloid concentration, the adsorbed PEO layers c...
Article
1H spin-spin relaxation rate constant, R2, of water was measured by using the Carr-Purcell-Meiboom-Gill sequence in aqueous solutions of native cyclodextrins (alpha, beta, and gamma-CD) and chemically modified CDs in order to probe the structuring of the water surrounding these cyclic carbohydrate molecules. R2 values for water in solutions contain...
Article
A polyurethane consisting of six blocks of polyethylene glycol and five blocks of hexamethylene diisocyanate was synthesized. The influence of the addition of R-cyclodextrin (R-CyD) on the lower critical solution temperature behavior of the polyurethane was investigated by “cloud point” measurements, and the dependence of the phase state (solution,...
Chapter
The structural interaction between the anionic surfactant sodium dodecyl sulphate (SDS) and the bipolymer gelatin has been studied using small-angle neutron scattering. In particular, neutron scattering length contrast variation has been used to highlight the structures of the components of the mixture both separately and together. Some aspects of...
Article
We study the effect of adding trimethylsilyl-treated polysilicate nanoparticles (Rg∼2.2nm) to crosslinked poly(dimethylsiloxane) (PDMS) elastomers above the entanglement molecular weight. The results are compared to un-crosslinked PDMS of a similar molecular weight, reported in previous studies and filled with the same polysilicate nanoparticles.Th...
Article
Sodium polyacrylate is well known for its application as a scale inhibitor in common household products, and the effects of both monovalent and divalent metal cations on its structure have been covered by a range of previous publications. In the present article, we extend this work by using solvent relaxation NMR to look at the adsorption of the po...
Article
Full-text available
The diffusion constants of carboxylated acrylic copolymers in isopropanol (IPA) have been investigated using the PFG NMR technique. A range of compositions of butyl methacrylate and methacrylic acid random copolymers (BMA–MAA 100/0 through to 60/40 in 10 mol% steps) have been studied. The polymer diffusivity is two orders of magnitude slower than t...
Article
Full-text available
The diffusion constants of solvent in solutions of carboxylated acrylic random copolymers in isopropanol (IPA) have been investigated using the PFG NMR technique. The copolymers are composed of butyl methacrylate and methacrylic acid with a range of molar ratios (BMA/MAA 100/0 through to 60/40 in 10mol% steps). It was found that the echo attenuatio...
Article
Full-text available
A microfluidic device has been used to create novel monodisperse polymeric oil-in-water emulsions of diameter 15–100 µm, stabilised by surfactants and polymers. The pulse field gradient nuclear magnetic resonance (PFG-NMR) signal attenuation function showed minima that allow a simple calculation of the droplet size and polydispersity. The presence...
Chapter
The sections in this article are
Article
Solvent relaxation NMR and small-angle neutron scattering have been used to characterize adsorbed poly(ethylene oxide) (PEO) layers on silica at a range of surfactant and electrolyte concentrations. Below the critical aggregation concentration (cac), the results suggest that sodium dodecyl sulfate (SDS) interacts relatively weakly, perhaps analogou...
Article
A range of different stabilizers have been used to render natural kaolin clay particles hydrophobic and dispersible in nonpolar solvents such as heptane. Both silanol and aluminol groups are known to be present at the kaolin surface. Use of a Hammett indicator showed that silanes would not neutralize the acidic aluminol sites, whereas amines would...
Article
Molecular dynamics simulations were performed to study the behavior of nanoscale water droplets at solid surfaces. Simulations of droplets on heterogeneous patterned surfaces show that the relative sizes of the domains and the droplets play an important role as do the interactions between the solid and the liquid, particularly when the domain width...
Article
Small-angle neutron scattering has been used to investigate the associative structures formed by triblock copolymers of poly(ethylene oxide) (PEO)-polypropylene oxide (PPO)-poly(ethylene oxide) (PEO) (also known as Pluronics) and to monitor the structural changes occurring upon complexation with heptakis(2,6-di-O-methyl)-beta-cyclodextrin (hbeta-CD...
Article
The steric interaction potential between colloidal particles imparted by adsorbed polymer layers is directly related to their structure. Due to the complexity of these interfacial structures, the steric potential may behave differently at different interparticle separations. In this study, we proposed a combined model of the equivalent hard-sphere...
Article
A Monte Carlo simulation method has been developed for modelling amphiphiles at an oil-water interface. Properties are calculated for the mixture water, benzene and tetraoxyethylene glycol dodecyl ether.
Article
The effects of various electrolytes on the adsorption of poly(ethylene oxide) onto silica have been studied. The salts were the chlorides of Na+, Mg2+, Ca2+, and La3+. The methods used were adsorption isotherms, found using a depletion method with phosphomolibdic acid, photon correlation spectroscopy, and solvent relaxation NMR. All the salts incre...
Article
Small-angle neutron scattering was used to investigate the interactions in concentrated colloidal dispersions containing silica or polystyrene latex with adsorbed polyethyleneoxide (PEO). In these dispersions of charged particles, both electrostatic and steric repulsions are present. The PEO layer was made invisible to neutrons through contrast mat...
Article
Cyclomaltooligosaccharides (cyclodextrins, CDs) are cyclic oligomers having six, seven, or eight units of alpha-D-glucose, named as cyclomaltohexaose (alpha-CD), cyclomaltoheptaose (beta-CD) and cyclomaltooctaose (gamma-CD), respectively. The molecule of CD has a cavity in which the interior is hydrophobic relative to its outer surface. The solubil...
Article
The structure factors of colloidal silica dispersions at rather high volume fractions (from 0.055 to 0.22) were measured by small-angle X-ray scattering and fitted with both the equivalent hard-sphere potential model (EHS) and the Hayter-Penfold/Yukawa potential model (HPY). Both of these models described the interactions in these dispersions succe...
Article
Polystyrene (PSt)-based copolymer colloidal microgels consisting of a hydrophilic hydrogel layer, such as poly(methacrylic acid) (PMAA) or poly(N-isopropyl acrylamide) (PNIPAM), were synthesized through emulsifier-free polymerization. The morphology and particle size of the microgel particles were characterized using a combination of TEM and photon...
Article
Small-angle neutron scattering (SANS) studies of aqueous dispersions of Stöber silica particles (which have been hydrophobised by having 1-octadecanol grafted to their surface), carrying an adsorbed layer of the nonionic surfactant C12E24, in water, have been performed as a function of temperature. Using mixtures of D2O and H2O, the composition of...
Article
The dynamics of solvent inside swelling microgel particles is studied using 1H NMR. Solvent relaxation is sensitive to the microgel volume transition after temperature changes, showing the effect of the local environmental conditions on solvent confinement. A microscopic view of the volume phase transition of microgel particles is then shown. NMR m...
Article
This paper discusses the dynamics of water molecules in poly(NIPAM) microgel dispersions. 1H NMR spectroscopy is used to determine the self-diffusion coefficient of the water molecules. The capability of the microgel particles to restrict the motion of water molecules depends on the degree of swelling, as determined by dynamic light scattering. The...
Article
The surfactant-free synthesis of latex polymers of styrene and sodium styrenesulfonate (NaSS) was investigated. The development of size and size distribution of the particles was studied by photo-correlation spectroscopy (PCS) and transmission electronic microscopy (TEM). The effects of NaSS concentration and the order of addition of reactants were...
Article
Small-angle neutron scattering (SANS) was used to investigate the interparticle interactions in concentrated dispersions of colloidal silica stabilized either by steric or by electrostatic repulsive interactions. In 10 mM NaCl, an adsorbed PEO layer is required to prevent flocculation, and particles are stabilized by steric repulsions. The adsorbed...
Article
The self-assembly into nanotubes in solution of an amphiphilic copolymer is characterized by small-angle neutron scattering (SANS). This study confirmed the shape and the size of the tubular association and the 3-D association of the tubes predicted by molecular orbital theory. Moreover, the characterization of the stability of the association has...
Article
The adsorption of selected poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) tri-block copolymers on synthetic clay particles (laponite) has been investigated. The adsorbed amount and distribution of polymer was determined as a function of relative block composition and size, using the technique of contrast variation sma...