The effect of cross-link density on the structure Poly-(N-isopropylacrylamide) microgel particles prepared by emulsion polymerization was investigated static and dynamic light scattering measurements. According to these measurements gel cannot be considered as homogeneous spheres. strongly depends degree cross-linking. At high can described with a Gaussian segment distribution. With decreasing tends toward that highly branched coil.

The adsorption on silica wafers of a hyperbranched, high molecular weight polyethylenimine (PEI) was investigated using reflectometry. pH and ionic strength dependence PEI kinetics that the adsorbed amount were interpreted according to complex balance segment/segment segment/surface site interactions. observed properties show significant deviations from recently studied features polyvinylamine cellulose coated silicas. different behavior can be attributed pronounced difference in...

The binding isotherm of sodium dodecyl sulfate (SDS) on a hyperbranched polyethyleneimine (PEI) was determined by an equilibrium dialysis method. Dynamic light scattering, electrophoretic mobility, and coagulation kinetics measurements were also performed in order to monitor the changes charged nature size PEI/SDS complexes. experimental shows that SDS interacts with PEI two different ways. In first process, ions bind monomer form protonated amine groups, which is accompanied increase pH. A...

A thermodynamic analysis of the interaction between fourteen different molar mass poly(ethylene oxide)s (PEO) and sodium dodecyl sulfate (SDS) based on measured surfactant-binding isotherms is given. The were determined by potentiometric method in presence 0.1 M inert electrolyte (NaBr). It was found that there no PEO/SDS complex formation if MPEO < 1000. In molecular weight range 1000 8000, critical aggregation concentration (cac) surfactant number are decreasing as polymer increases....

The role of polymer charge density in the kinetics adsorption and desorption, on silica, polyelectrolyte poly(ethyleneimine) (PEI) was investigated by stagnation-point flow reflectometry. In first series experiments, PEI solutions were introduced at same ionic strength pH as background solvent. It found that adsorbed amount increased increasing pH. second investigations, several with ascending consecutively into cell. these cases, a stepwise buildup observed "final" amounts to be roughly...

The effect of different mixing protocols on the charged nature and size distribution aqueous complexes hyperbranched poly(ethylene imine) (PEI) sodium dodecyl sulfate (SDS) was investigated by electrophoretic mobility dynamic light scattering measurements at pH values, polyelectrolyte concentrations, ionic strengths. It found that large excess surfactant a colloidal dispersion individual PEI/SDS nanoparticles forms via an extremely rapid components means stop−flow apparatus. However,...

The impact of an electrolyte on aqueous mixtures oppositely charged macromolecules and surfactants is usually explained by assuming equilibrium association between the components. In this work, it shown that nonequilibrium character polyelectrolyte/surfactant systems plays a crucial role in interpretation effect salt. Experimental investigations sodium poly(styrenesulfonate) (PSS) hexadecyltrimethylammonium bromide (CTAB) reveal two distinct effects added chloride (NaCl). At small moderate...

A novel method is presented for the design of robust, sustained nanochemomechanical oscillators. The approach based on switching chemoresponsive nanogel beads between their collapsed and swollen state by coupling them to an appropriately chosen nonlinear reaction. system utilizes a proton activated oscillatory reaction pH-sensitive nanobeads gel that provide more than order magnitude volume change. key point our control colloid stability in wide range experimental parameters (pH, ionic...

Biodegradable, biocompatible nanoparticles with tuneable fluorescence - due to their great potential in biology, medicine and sensor development are widely studied nowadays. Recently it was shown that the complex red emitting spectroscopic feature of Bovine Serum Albumin gold (BSAAu) bioconjugates can be related versatility conformational changes BSA protein. In our study, we performed a comprehensive study on structural host molecules by infrared spectroscopy (FTIR) small-angle X-ray...

One of the most important characteristics polyelectrolyte/surfactant interaction is binding isotherm surfactant because it provides basic thermodynamic information about mechanism. However, amount bound to polymer may crucially affect surface properties these systems via changing activity components. Therefore, a knowledge isotherms can also be useful in tuning efficiency commercial products. determination still subject significant experimental difficulties. In this letter, we offer novel...

The effect of uncharged surfactant additives on the oppositely charged polyion/ionic complexation is usually described as a direct equilibrium association between polyelectrolyte molecules and free mixed micelles analogous to polyion/colloidal particle interactions. This approach predicts that binding ionic can be completely suppressed by increasing nonionic-to-ionic ratio. In present work, it shown addition nonionic surfactants poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate...

Experimental results are presented on the counterion dependence of adsorption alkali (Li+, Na+, K+, Rb+ and Cs+) decyl sulfates at air/solution interface. The isotherms calculated from equilibrium surface tension vs. concentration data by means Gibbs equation show significant dependence. We propose a theoretical model based Gouy–Chapman–Stern theory for description ionic surfactant is physical picture that counterions can enter among headgroups if hydrated size smaller than headgroups. In...

The effect of different mixing protocols on the bulk and surface properties aqueous mixtures linear poly(vinylamine) (PVAm) sodium dodecyl sulfate (SDS) has been investigated using pH, electrophoretic mobility, dynamic light scattering, coagulation kinetics, tension measurements. For preparation solutions, two kinds were applied. so-called "stop flow mixing" enables a very rapid whereas in case "gentle components is less efficient. At high surfactant concentrations kinetically stable colloid...

The complexation between hexadecyl- and dodecyltrimethylammonium bromides (CTAB DTAB) with sodium poly[(vinyl alcohol)-co-(vinyl sulfate)] (PVAS) copolymer of low charge density has been investigated using pyrene fluorescence spectroscopy, electrophoretic mobility, turbidity, dynamic light scattering measurements. results indicate that the binding cationic surfactant occurs in three steps. At concentrations, amphiphile binds to vinyl sulfate groups. Above neutralization, may occur on surface...

Experimental results are presented on the adsorption of sodium alkyl sulfate homologues (nC = 8−14) at air/solution interface. The isotherms calculated from equilibrium surface-tension vs concentration data and critical micelle change regularly with length chain; odd/even effect was not observed. were analyzed using a model-independent approach. analysis indicates that total driving force reaches plateau value becomes constant in function adsorbed amount case each homologue. With use...

The aggregation of polyelectrolyte–surfactant particles has been investigated at large excess the surfactant in presence NaCl using coagulation kinetics, electrophoretic mobility and dynamic light scattering measurements. systems were mixtures sodium dodecyl sulfate (SDS) with poly(vinylamine) (PVAm) as well poly(diallyldimethylammonium chloride) (PDAC). observed variation initial rate concentration PVAm–SDS PDAC–SDS is qualitative agreement predictions DLVO theory. This finding provides...

We report on chemical stability and corrosion behavior of highly depolymerized sulfophosphate glasses from the system ZnO – Na 2 O SO 3 P 5 in aqueous solution, providing data weight loss, ion release rates, modifications surface topology as a function time, temperature pH value. Observations seem consistent with previously developed structural model heterogeneity, where cations + Zn 2+ cluster selectively vicinity sulfate phosphate anions, respectively.

LZSA (Li 2 O-ZrO -SiO -Al O 3 ) glass ceramic system has shown high potential to obtain LTCC laminate tapes at low sintering temperature (&lt;1000 ° C) for several applications, such as screen-printed electronic components. Furthermore, ceramics offer interesting mechanical, chemical, and thermal properties, which make also a candidate fabricating multilayered structures processed by Laminated Objects Manufacturing (LOM) technology. The crystallization kinetics of an with composition 16.9Li...

We report on photoluminescence of vanadium-doped lithium zinc silicate glasses and corresponding nanocrystalline Li2ZnSiO4 glass ceramics as broadband UV-to-VIS photoconverters. Depending dopant concentration synthesis conditions, VIS photoemission from [VO4]3 is centered at 550-590 nm occurs over a bandwidth (FWHM) ~250 nm. The excitation band covers the complete UV-B to UV-A spectral region. In as-melted glasses, emission lifetime about 34 μs up nominal 0.5 mol%. ceramic, it increases 45...

The aggregation of the negatively charged complexes hyperbranched poy(ethylenimine) (PEI) and sodium dodecyl sulfate (SDS) has been investigated at different chloride (NaCl) concentrations using coagulation kinetics, electrophoretic mobility dynamic light scattering measurements. observed variation initial rate with NaCl concentration indicates formation kinetically stable colloid dispersions in composition pH range. These are electrostatically stabilized due to adsorption excess ions on...