A novel series of polymeric surfactants based on carboxy methyl cellulose and alkyl poly(etheroxy) acrylate were synthesized by ultrasonic irradiation. These polymeric surfactants have exhibit excellent surface activity due to their unique structure. The influences of salt, alcohol and alkali on the interfacial activity of these polymeric surfactants were studied by interfacial tensiometery, dynamic laser scattering (DLS), UV spectroscope and environmental scanning electrical microscope (ESEM). The surface tension and interfacial tension (IFT) properties change little with NaCl added. The formed micelles shrink, their size becomes smaller. Alcohols cause the IFT to decrease a little because a small amount of free chains present in solution. Under the influence of added alkali, the IFT of the polymeric surfactants, in aqueous solution, decreases so much that sometimes it is less than 10−2 mN/m. Using data from the equivalent alkane scan, one cannot draw the conclusion that the action of alkali with the acidic components in crude oil leads to the ultra-low IFT. The analyses by UV, DLS and ESEM show that the micelles formed by polymeric surfactants could be disaggregated or destroyed sharply by the action of alkali. So the size of micelles decreases greatly and the number of free chains increases. That more polymeric surfactants molecules move to the interface of oil/water and rearrange at the interface of oil/water is believed to be the main reason of the ultra-low IFT (10−3 mN/m) that is obtained. 相似文献
For polyelectrolyte complex between cationic surfactant and polyanion, the adsorptive voltammetry at carbon paste electrode using an electroactive cationic surfactant was examined. The adsorption state of the cationic surfactant in the complexes at CPE was estimated from the half‐height width of the oxidation waves. The half‐height width for poly(styrene sulfonate) was independent of the molecular weight, and was same as that for poly(vinyl sulfate). The half‐height width for heparin was broad and different from that of the vinyl polyanions. According to the analysis by Frumkin isotherm, the interaction between cationic surfactants was attractive in heparin complex at CPE, however, in the vinyl polyanion complexes at CPE the interaction was non‐cooperative as that predicted with the Langmuir isotherm. In spite of the same adsorption state, the concentration dependency of the peak current for poly(styrene sulfonate) was quite different from that for poly(vinyl sulfate). The concentration dependence indicated the reactive property of each polyanion on the association with the cationic surfactant in aqueous solution. 相似文献
Small angle X-ray scattering (SAXS) is measured for the lamellar phase in aqueous systems of 1-o-β-3,7-dimethyoctyl-D-glucopyranoside (β-Glc(Ger)), which has recently been prepared by us, 1-o-β-decyl-D-glucopyranoside (β-GlcC10), and 1-o-β-octyl-D-glucopyranoside (β-GlcC8). The repeat distance d obtained from the position of the diffraction peak does not follow the swelling law d = 2δhc/hc, where δhc and hc are the thickness and the volume fraction of the hydrophobic layer, respectively. This may result from the fact that δhc increases and, equivalently, the surface area per surfactant molecule (as) decreases with increasing concentration. So we calculate δhc and as from the observed d value at each concentration using the above swelling law. The half-thickness δhc increases in the order β-GlcC8 < β-Glc(Ger) < β-GlcC10 at a fixed concentration. On the other hand, the data on as for β-GlcC10 and β-GlcC8 lie on the same line and the data for β-Glc(Ger) lies above this line. These results suggest that the cross-sectional area of the geranyl chain is larger than that of the glucose headgroup. Existence of water filled defects in bilayer sheets is also discussed based on the SAXS pattern and the concentration dependence of d. 相似文献
A non ionic surfactant with a rigid rod-like hydrophobic group has been synthesized. Owing to the molecular geometry of the surfactant only lamellar micelles are formed in aqueous solution.This system exhibits a lyotropic nematic phase (NL), which for the first time has been found for a binary non ionic surfactant/water system.Herrn Professor Dr. H.-G. Kilian mit herzlichen Glückwünschen zum 60. Geburtstag gewidmet. 相似文献
The inhibition of lingninase by hydrogen peroxide in the presence of cationic surfactant CTAB was studied by kinetic speetrophotometdc technique. Results showed that addition of CTAB enhanced the inhibition by H202, but it did not alter the inhibition pattern and the inhibition constant changed little with theco-ncentration of CTAB. Modification of the enzymic protein by the surfactant monomer may be responsible for the above mentioned results. 相似文献
The Gemini surfactant 9B-4-9B containing sodium sulfonate as hydrophilic head group was synthesized based on nonylphenol and characterized by FTIR, 1H NMR spectroscopy and the surface tension measurement. The CMC and C20 of the 9B-4-9B were smaller than that of sodium dodecylbenzene sulfonate and sodium dodecylsulfate, respectively, indicating excellent efficiency of micelle formation and reduced surface tension. Conducting polyaniline salts were synthesized by chemical oxidative micellar polymerization of aniline in water firstly using Gemini surfactant 9B-4-9B as the micelle stabilizer and ammonium peroxydisulfate as the oxidant at 0 °C. The stable polyaniline dispersions have been obtained when the molar ratio of the 9B-4-9B to aniline was equal to or above 0.5 used in the polymerization system. The obtained granular polyaniline particles with the size of 1-2 μm were characterized by FTIR, UV-Vis, SEM, WAXD and conductivity measurement. 相似文献
The adsorption of a surfactant mixture, based on an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS) and a nonionic
surfactant (Triton X-100, or TX100), on alumina nanoparticles was determined by solution depletion method combined with spectrometric
measurement. It is shown that the light scattering, originated from the residual adsorbent alumina particles in the supernatant
after centrifugation separation, interferes with the measurements of absorbance of the surfactant molecules, and therefore
constitutes an error source for determination of the surfactant concentration in the supernatant by spectrometric means. The
intensity of this light scattering, namely the influence of the residual alumina nanoparticles upon the surfactant adsorption,
was related to the surfactant adsorption and its equilibrium concentration and varied among a batch. In this paper we report
a Kalman filter method in order to eliminate the variational scattering background caused by non-separated residual alumina
nanoparticles in each supernatant. This method is of interest as it is simple, easy to carry out and of high precision. 相似文献
The main techniques developed to characterize chitosan are recalled. The interaction of chitosan with oppositely charged surfactants was investigated giving very important surface activity effects. A few chemical modifications are described and the new properties obtained are mentioned: alkylation gives amphiphilic polymers having interesting thickening behavior; grafting cyclodextrin (chit‐CD) gives a polymer able to include hydrophobic molecules; grafting adamantane gives an amphiphilic polymer able to specifically interact with chit‐CD forming a temporary network with gel‐like behavior.
The viscosities of adamantane‐chitosan, cyclodextrin‐chitosan, and unmodified chitosan solutions studied here. 相似文献
Adsorption of the anionic surfactant sodium dodecylsulfate (SDS) as well as competitive adsorption of SDS with the nonionic surfactant Triton X-405 on a polystyrene latex has been examined by the use of small-angle x-ray scattering (SAXS). Since the latex particles only have a low contrast towards water whereas the electron densities of the added surfactants are rather high, their gradual adsorption can be monitored with good sensitivity. The particles covered with SDS have been investigated by the contrast variation method. A distinct core-shell structure has been observed. After maximum coverage of the surface is reached, the additional surfactant forms free micelles. The analysis presented here allows the simultaneous investigation of the covered particles and the free micelles. This is due to their respective characteristic scattering contributions in different angular ranges. Information on the competitive adsorption could be obtained by analyzing the structure of the coated particles and the composition of the free mixed micelles. The adsorption is shown to be an equilibrium process where adsorption of the nonionic component is found to be much stronger than of the SDS molecules. 相似文献