Development of CuO/Cu(OH)SO Nanoparticle Mixtures to Optimize the HS Adsorption.

In this paper, we report the HS adsorption behavior of a sorbent composed of mixtures of tenorite (CuO) and brochantite [Cu(OH)SO]. These materials are readily prepared through the addition of NaOH to CuSO. They can be loaded onto polymer foams to create effective filters that can remove malodorous HS gas, as evidenced by breakthrough tests.

Slippery Alkoxysilane Coatings for Antifouling Applications.

Herein, we report the wettability and antifouling behavior of a range of different siloxane coatings on plastic and glass substrates. The films investigated are prepared using trimethoxysilane precursors with different alkyl chain lengths (1-18 C atoms) in order to study how the nature of the hydrophobic group affects the different parameters used to characterize wettability (contact angles, sliding angles, and contact angle hysteresis). Atomic force microscopy analysis shows that the coatings possess low surface topography [root mean squared roughness (rms) < 50 nm] and are highly transparent as studied using UV-vis spectroscopy.

Interaction of Surface-Modified Alumina Nanoparticles and Surfactants at an Oil/Water Interface: A Neutron Reflectometry, Scattering, and Enhanced Oil Recovery Study.

The evaluation of the mechanism of nanoparticle (NP)/surfactant complex adsorption at the critical oil/water interface was studied. A sophisticated technique (neutron reflectometry) was used to give a unique insight on NP/oil interactions in oil recovery systems. Herein, the adsorption of two modified alumina NPs with different degrees of hydrophobicity [hydrophilic = 2-[2-(2-methoxyethoxy)ethoxy]acetic acid and hydrophobic = octanoic acid (OCT)] stabilized with two different surfactants were studied at the oil/water interface.

Water-in-CO Microemulsions Stabilized by an Efficient Catanionic Surfactant.

To facilitate potential applications of water-in-supercritical CO microemulsions (W/CO μEs) efficient and environmentally responsible surfactants are required with low levels of fluorination. As well as being able to stabilize water-CO interfaces, these surfactants must also be economical, prevent bioaccumulation and strong adhesion, deactivation of enzymes, and be tolerant to high salt environments. Recently, an ion paired catanionic surfactant with environmentally acceptable fluorinated C tails was found to be very effective at stabilizing W/CO μEs with high water-to-surfactant molar ratios () up to ∼50 (Sagisaka, M.

New insights into the interactions between asphaltene and a low surface energy anionic surfactant under low and high brine salinity.

Hypothesis: The hyperbranched chains on the tail of low surface energy surfactants (LSES) causes lowering of surface free energy and rock wettability alteration, offering significant improvement in oil recovery in asphaltene oil reservoirs.

Experiments: Oil sweep efficiency was determined by fluid displacement in pure brine and LSES-brine solutions in a microfluidic pattern that was representative of a sandstone cross-section. Interfacial tension (IFT), wettability alteration, Raman and X-ray photoelectron spectroscopy (XPS) were used to measure the changes of asphaltene interactions with oil-aged substrate after surface treating with brine and surfactant-brine solutions.

Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface.

Hypothesis: Nanoparticle embedding into the surface of plastics provides an effective anchor that improves the durability of coatings formed from functionalized nanoparticles. Coatings formed from thermally embedded particles show superior wear resistance relative to coatings formed from non-embedded particles. As a consequence of this, embedded nanoparticles functionalized with hydrophilic and hydrophobic carboxylates are better suited for controlling the wettability of plastics than when the nanoparticles are deposited onto the plastic under ambient conditions.

Comparison of hydrophobicity and durability of functionalized aluminium oxide nanoparticle coatings with magnetite nanoparticles-links between morphology and wettability.

Hypothesis: The wetting characteristics of coatings created using functionalised nanoparticles and adhesive resins, depends strongly on the particle distribution within the surface layers. Although it has been shown that commercially available adhesives improve the durability of hydrophobic nanoparticle coatings, the wettability of these surfaces is governed by the agglomeration behaviour of the particles within the adhesive. As a consequence of this, coatings where the particles are highly agglomerated within the adhesive show lower hydrophobicity.

Size and morphology dependent surface wetting based on hydrocarbon functionalized nanoparticles.

Hypothesis: The wetting properties of films created using metal oxide nanoparticles can be controlled through roughness and chemical functionality; however, other variations such as the size and shape of the particles play an important role in improved understanding of the wetting behaviour of these materials.

Experiments: Infrared (IR) spectroscopy and thermogravimetric analysis (TGA) were used to study the chemisorption and grafting density of a carboxylic acid onto the surface of nanoparticles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to investigate the morphology and roughness of the nanoparticle films.

A new family of urea-based low molecular-weight organogelators for environmental remediation: the influence of structure.

Gelation processes grant access to a wealth of soft materials with tailorable properties, in applications as diverse as environmental remediation, biomedicine and electronics. Several classes of self-assembling gelators have been studied and employ non-covalent bonds to direct assembly, but recently attention has come to focus on how the overall shape of the gelator molecule impacts its gelation. Here we study a new sub-family of low molecular weight organogelators and explore how steric rearrangement influences their gelation.

Aqueous electromigration of single-walled carbon nanotubes and co-electromigration with copper ions.

The electromigration behaviour of raw and acid purified single walled carbon nanotubes (SWCNTs) in dilute aqueous systems (0.0034 mg mL), in the absence of surfactant, with the addition of either 0.85 M acetic acid or 0.

Tunable Surface Properties of Aluminum Oxide Nanoparticles from Highly Hydrophobic to Highly Hydrophilic.

The formation of materials with tunable wettability is important for applications ranging from antifouling to waterproofing surfaces. We report the use of various low-cost and nonhazardous hydrocarbon materials to tune the surface properties of aluminum oxide nanoparticles (NPs) from superhydrophilic to superhydrophobic through covalent functionalization. The hydrocarbon surfaces are compared with a fluorinated surface for wettability and surface energy properties.

Assembly of porous hierarchical copolymers/resin proppants: New approaches to smart proppant immobilization via molecular anchors.

Hypothesis: The assembly of temperature/pH sensitive complex microparticle structures through chemisorption and physisorption provides a responsive system that offers application as routes to immobilization of proppants in-situ.

Experiments: Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) along with energy dispersive X-ray analysis (EDX) have been used to characterize a series of bi-functionalized monolayers and/or multilayers grown on alumina microparticles and investigate the reactive nature of both temperature sensitive cross-linker (epoxy resin) with the layers and pH-responsive bridging layer (polyetheramine).

Findings: The bifunctional acids, behaving as molecular anchors, allow for a controlled reaction with a cross-linker (resin or polymer) with the formation of networks, which is either irreversible or reversible based on the nature of the cross-linker.

Branched Hydrocarbon Low Surface Energy Materials for Superhydrophobic Nanoparticle Derived Surfaces.

We present a new class of superhydrophobic surfaces created from low-cost and easily synthesized aluminum oxide nanoparticles functionalized carboxylic acids having highly branched hydrocarbon (HC) chains. These branched chains are new low surface energy materials (LSEMs) which can replace environmentally hazardous and expensive fluorocarbons (FCs). Regardless of coating method and curing temperature, the resulting textured surfaces develop water contact angles (θ) of ∼155° and root-mean-square roughnesses (Rq) ≈ 85 nm, being comparable with equivalent FC functionalized surfaces (θ = 157° and Rq = 100 nm).

Properties of surfactant films in water-in-CO2 microemulsions obtained by small-angle neutron scattering.

Hypothesis: The formation, stability and structural properties of normal liquid phase microemulsions, stabilized by hydrocarbon surfactants, comprising water and hydrocarbon oils can be interpreted in terms of the film bending rigidity (energy) model. Here, this model is tested for unusual water-in-CO2 (w/c) microemulsions, formed at high pressure with supercritical CO2 (sc-CO2) as a solvent and fluorinated surfactants as stabilizers. Hence, it is possible to explore the generality of this model for other types of microemulsions.

Hyperbranched hydrocarbon surfactants give fluorocarbon-like low surface energies.

Two series of Aerosol-OT-analogue surfactants (sulfosuccinate-type di-BCnSS and sulfoglutarate-type di-BCnSG) with hyperbranched alkyl double tails (so-called "hedgehog" groups, carbon number n = 6, 9, 12, and 18) have been synthesized and shown to demonstrate interfacial properties comparable to those seen for related fluorocarbon (FC) systems. Critical micelle concentration (CMC), surface tension at the CMC (γCMC), and minimum area per molecule (Amin) were obtained from surface tension measurements of aqueous surfactant solutions. The results were examined for relationships between the structure of the hedgehog group and packing density at the interface.

Aggregation behavior of polyisoprene-pluronic graft copolymers in selective solvents.

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 ethanol and hexane and in a nonselective solvent, tetrahydrofuran (THF). The results indicated that, in a selective solvent for the side chain Pluronics (e.

Low-surface energy surfactants with branched hydrocarbon architectures.

Surface tensiometry and small-angle neutron scattering have been used to characterize a new class of low-surface energy surfactants (LSESs), "hedgehog" surfactants. These surfactants are based on highly branched hydrocarbon (HC) chains as replacements for environmentally hazardous fluorocarbon surfactants and polymers. Tensiometric analyses indicate that a subtle structural modification in the tails and headgroup results in significant effects on limiting surface tensions γcmc at the critical micelle concentration: a higher level of branching and an increased counterion size promote an effective reduction of surface tension to low values for HC surfactants (γcmc ∼ 24 mN m(-1)).

Interaction between surfactants and colloidal latexes in nonpolar solvents studied using contrast-variation small-angle neutron scattering.

The interaction between deuterium-labeled Aerosol OT surfactant (AOT-d34) and sterically stabilized poly(methyl methacrylate) (PMMA) latex particles dispersed in nonpolar solvents has been studied using contrast-variation small-angle neutron scattering (CV-SANS). The electrophoretic mobilities (μ) of the latexes have been measured by phase-analysis light scattering, indicating that μ is negative. Two analogues of the stabilizers for the particles have been studied as free polymers in the absence of PMMA latexes: poly(12-hydroxystearic acid) (PHSA) polyester and poly(methyl methacrylate)-graft-poly(12-hydroxystearic acid) (PMMA-graft-PHSA) stabilizer copolymer.

Shape transitions in supercritical CO2 microemulsions induced by hydrotropes.

The ability to induce morphological transitions in water-in-oil (w/o) and water-in-CO2 (w/c) microemulsions stabilized by a trichain anionic surfactant 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulfonate (TC14) with simple hydrotrope additives has been investigated. High-pressure small-angle neutron scattering (SANS) has revealed the addition of a small mole fraction of hydrotrope can yield a significant elongation in the microemulsion water droplets. For w/o systems, the degree of droplet growth was shown to be dependent on the water content, the hydrotrope mole fraction, and chemical structure, whereas for w/c microemulsions a similar, but less significant, effect was seen.

Effect of temperature, cosolvent, and added drug on Pluronic-flurbiprofen micellization.

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), while increasing the repulsive interactions between the flurbiprofen-Pluronic spherical complexes. However, increasing temperature and addition of drug increases both the aggregation number and core radius and leads to a more dehydrated core.

Growth and shrinkage of pluronic micelles by uptake and release of flurbiprofen: variation of pH.

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 increase in the fraction of micellization, aggregation number, and the core radius of the micelles. However, changing the pH to above the pKa of flurbiprofen in an ethanol/water mixture (∼6.

Flurbiprofen encapsulation using pluronic triblock copolymers.

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 micellization.