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The phase behavior and microstructure of A–B-type silicone copolymer, Me3SiO–(Me2SiO)m −2–Me2SiCH2CH2CH2–O–(CH2CH2O)51.6H, (abbreviated as POE–PDMS or SimC3EO52) in water was investigated for a constant POE chain length (EO52) at 25 °C to ascertain the effect of PDMS chain length (m ranging from 5.8 to 52) on the phase behavior. Different microstructures, such as discontinuous micellar cubic (I...
The solubilities of two types of lipids, triglycerides (TG), weakly polar compounds, and stearylamine (SA), a polar molecule, within phospholipid bilayers of vesicles are examined by time-resolved selective solubilisation and compared. Both TG and SA were added to phosphatidylcholine (Lipoid E80, PL) vesicles at different concentrations ranging from 0 to 20% (weight per weight of PL). TG insertion...
Dowanols being chemically ethers of n-alkanols with bis(isopropylene glycol) represent characteristic properties of hydrotropic molecules or “solvo-surfactants”, i.e. they have some surfactant properties in addition to typical solvent properties. The dynamic surface tension behaviour of aqueous Dowanol solutions (c ≤ 10–1 M) is a consequence of different surface-active components owing to the presence...
The aim of this work was the design of a pH-sensitive system consisting of an amphiphilic polymer and a β-cyclodextrin coepichlorhydrin water-soluble polymer (pβCD/EP). Different modified dextrans were synthesized from reaction of dextran (Mw=40,000) with phthalic anhydride, 2-phenylglutaric anhydride and 1,2-cyclohexane dicarboxylic anhydride with grafting ratio around 2%. The viscometric study...
We have studied the variation in the aggregate size, shape and the unit cell of the rectangular ribbon (R1) phase formed between the hexagonal (H1) and the lamellar phase with water defects (LαH phase) in the potassium N-dodecanoyl-dl-alaninate/water/1-decanol system. With an increase in surfactant concentration at roughly constant decanol concentration, the aspect...
The effect of phenol addition to the aqueous phase on the critical micelle concentration and molar enthalpy of micellisation of alkanediyl-α,ω-bis(dodecyldimethylammonium bromide) Geminis (referred to as C12CSC12, where S is the spacer length) has been studied at 298 K. For C12C2C12, specific conductivities of aqueous surfactant solutions were measured over concentration ranges about the respective...
Well-defined amphiphilic cylindrical polymer brushes with a poly(acrylic acid) core and a poly(n-butyl acrylate) shell were synthesized via atom transfer radical polymerization. Unimolecular polymer cylinders were directly visualized on mica by scanning force microscopy. The hydrophilic cores of the brushes, poly(acrylic acid), were neutralized by NaOH and afterwards reacted with Fe3+ and Fe2+ cations...
We present the synthesis of hyperbranched polymer–silica hybrid nanoparticles by self-condensing vinyl polymerization (SCVP) via atom transfer radical polymerization (ATRP) from silica surfaces. ATRP initiators were covalently linked to the surface of silica particles, followed by SCVP of an initiator-monomer (“inimer”) which has both a polymerizable acrylic group and an initiating group in the same...
Interpolyelectrolyte complexes have been prepared by mixing in aqueous solutions an anionic polymer, a neutral β-cyclodextrin polymer and a cationic surfactant dodecyltrimethylammonium chloride. In this ternary system, electrostatic interactions are involved between the opposite charges of the surfactant and the anionic polymer, whereas inclusion complex interactions link the surfactant to the neutral...
We have investigated molecular interactions between a charged monolayer of different lipid compositions with a polyelectrolyte at the air–water interface by means of Langmuir isotherm measurements and between charged liposomes in an aqueous suspension by means of light scattering measurements, respectively. The condensing effect of the ionic character of the subphase the stability of the mixed monolayers...
Axisymmetric drop shape analysis has been applied to provide a first insight into the adsorption kinetics and surface viscoelasticity of perfluoropolyether carboxylic salts at the water–air interface. The two surfactants Cl(C3F6O)nCF2COONH4, with two or three perfluoroisopropoxy units, n, have been examined in aqueous solution at molar concentrations well below their critical micelle concentration...
Mixtures of amphotericin B and synthetic phospholipids, differing in the saturation of the phosphatidylcholine acyl chains, such as dipalmitoyl phosphatidylcholine, palmitoyl-oleoyl phosphatidyl choline and dioleoyl phosphatidylcholine, have been studied as floating Langmuir monolayers at the air–water interface. The films were spread at room temperature on aqueous subphases of different pH (3, 6...
Spread monolayers of dipalmitoyl phosphatidylcholine, methyl palmitate and their mixtures were studied. For this purpose, the surface pressure (π)–average molecular area (A) isotherms were recorded using a Langmuir film balance. From the π-A results information on the mutual miscibility of the two components in the two-dimensional state was deduced. Then classical surface chemistry thermodynamic analysis...
In a previous study, the wetting of poly(tetrafluoroethylene) by aqueous solutions of a mixture of perfluoropolyether carboxylic salts was evaluated via dynamic contact angle measurements, assessing surfactant adsorption. In the present work, the two main components of that mixture, differing in chain length only, are used to explore their relative contribution to adsorption. Aqueous solutions of...
The main purpose of this article is to understand at the microscopic level the possible effect of the chain length on the properties of an adsorbed monolayer between two immiscible liquids. We report a molecular dynamics simulation study of an alkyltrimethylammonium chloride monolayer adsorbed in the water/isooctane interface. The surfactants studied have 8, 12 and 16 carbon atoms in the chain and...
We report studies on the influence of the introduction of an n-alkyl group in the 4′ position of an aromatic carboxylic acid (namely 5′-phenyl-m-terphenyl-4-carboxylic acid, PTCA). For this purpose, 4′-methyl and 4′-n-propyl PTCA were synthesized and investigated at the air/water interface. The monolayers were characterized by measuring the surface pressure and electric surface potential upon film...
Monodisperse nonionic fluorinated surfactants with oligooxyethyl monomethylated ethers as the hydrophilic head and a perfluoroalkyl tail as the hydrophobic moiety linked together through an N-sulfonylcarbamate function were synthesized in two steps with good yields. The evaluation of their behaviour at the air–water interface has been investigated at 20 °C by measurement of surface tension, γs,...
The surface potential at the ice–water interface was measured with an ice electrode as a function of pH. Equilibration in the basic region was found to be slow and no stable potential was obtained. In the pH region below 8 the equilibration was fast, yielding stable and accurate values of the surface potential. The effect of Na+>, K+ and Mg2+ ions was examined. It was found that these ions do not...
Biomedical applications of magnetic carriers are based on the specific interaction between the particle surface and ligands like meso-2,3-dimercaptosuccinic acid. Such cross-linking agents are polyfunctional Brönsted acids leading in aqueous media to several species the amounts of which vary strongly as a function of pH. Moreover, electrical double-layered magnetic colloids behave as a mixture of...
Diblock copolymers of poly(isobutyl vinyl ether-b-2-methyl-2-oxazoline) (PIBVE–POXZ) were synthesized by cationic polymerization. Copolymers with molecular weight from 1,000 to 4,000 g mol−1> had a composition of 20–50% of the IBVE block. They were adsorbed on porous silica particles from three different solvents:dichloromethane, which is a solvent of both blocks; water and cyclohexane, which are...
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