Quantitative Structure-Property Relationship on Prediction of Surface Tension of Nonionic Surfactants

A quantitative structure-property relationship (QSPR) study has been made for the prediction of the surface tension of nonionic surfactants in aqueous solution. The regressed model includes a topological descriptor, the Kier & Hall index of zero order (KH0) of the hydrophobic segment of surfactant and a quantum chemical one, the heat of formation (fHD) of surfactant molecules. The established general QSPR between the surface tension and the descriptors produces a correlation coefficient of multiple determination, 2r=0.9877, for 30 studied nonionic surfactants.

Studies on the Cloud Points of Nonionic Surfactants with QSPR

With quantum chemical parameters, topological indexes, and physical chemistry parameters as descriptors, a quantitative structure-property relationship（QSPR） has been found for the cloud points of four series of nonionic surfactants（ a total of 65 surfactants）. The best-regressed model includes six descriptors, and the correlation coefficient of multiple determination is as high as 0. 962.

Interaction of nonionic surfactant AEO_9 with ionic surfactants

The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammonium bromide (CTAB) at molar fraction of AEO9, A EO9 α =0.5. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γCMC), maximum surface excess concentration (Γmax) and minimum area per molecule at the air/solution interface (Amin) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were determined. Mixtures of both AEO9/SDS and AEO9/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.

Experimental investigation of wettability alteration on residual oil saturation using nonionic surfactants: Capillary pressure measurement

Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands.Among of all operative factors,wettability may be the foremost parameter affecting residual oil saturation in all stage of oil recovery.Although wettability alteration is one of the methods which enhance oil recovery from the petroleum reservoir.Recently,the studies which focused on this subject were more than the past and many contributions have been made on this area.The main objective of the current study is experimentally investigation of the two nonionic surfactants effects on altering wettability of reservoir rocks.Purpose of this work is to change the wettability to preferentially the water-wet condition.Also reducing the residual oil saturation(Sor)is the other purpose of this work.The wettability alteration of reservoir rock is measured by two main quantitative methods namely contact angle and the USBM methods.Results of this study showed that surfactant flooding is more effective in oil-wet rocks to change their wettability and consequently reducing Sor to a low value.Cedar(Zizyphus Spina Christi)is low priced,absolutely natural,and abundantly accessible in the Middle East and Central Asia.Based on the results,this material can be used as a chemical surfactant in field for enhancing oil recovery.

Interaction of Fluorocarbon Containing Hydrophobically Modified Polyelectrolyte with Nonionic Surfactants

The interaction of fluorocarbon containing hydrophobically modified polyelectrolyte (FMPAANa) with two kinds of nonionic surfactants (hydrogenated and fluorinated) in a semidilute (0.5 wt%) aqueous solution had been studied by rheological measurements. Association behavior was found in both systems. The hydrophobic interaction of FMPAANa with fluorinated surfactant (FC171) is much stronger than that with hydrogenated surfactant (NP7.5) at low surfactant concentrations. The interaction is strengthened by surfactants being added for the density of active junctions increased. Whereas distinct phenomena for FC171 and NP7.5 start to be found as the surfactants added over their respective certain concentration. The interaction of polyelectrolyte with fluorinated surfactant increases dramatical ly while that with hydrogenated surfactant decreases.

Prediction on Critical Micelle Concentration of Nonionic Surfactants in Aqueous Solution:Quantitative Structure-Property Relationship Approach

In order to predict the critical micelle concentration (cmc) of nonionic surfactants in aqueous solution,a quantitative structure-property relationship (QSPR) was found for 77 nonionic surfactants belonging to eight series. The best-regressed model contained four quantum-chemical descriptors,the heat of formation (ΔH),the molecular dipole moment (D),the energy of the lowest unoccupied molecular orbital (E_ LUMO ) and the energy of the highest occupied molecular orbital (E_ HOMO ) of the surfactant molecule; two constitutional descriptors,the molecular weight of surfactant (M) and the number of oxygen and nitrogen atoms (n_ ON ) of the hydrophilic fragment of surfactant molecule; and one topological descriptor,the Kier & Hall index of zero order (KH0) of the hydrophobic fragment of the surfactant. The established general QSPR between lg(cmc) and the descriptors produced a relevant coefficient of multiple determination:R 2=0.986. When cross terms were considered,the corresponding best model contained five descriptors E_ LUMO ,D,KH0,M and a cross term n_ ON ·KH0,which also produced the same coefficient as the seven-parameter model.

Overview of Simple Test for Determination of Surfactants by Adhesion Method

A simple, sensitive, and rapid analytical method is reported for the determination of surfactants. This is based on the use of an oppositely charged dye as the ion pair to form an ionic associate with the surfactant in a vessel, thus affording ion-associated adhesion on the inner wall of the vessel. After the adhesion, the remaining solution in the vessel is removed, and the ionic associate is dissolved in a suitable solvent. The absorbance of the resulting solution is measured spectrophotometrically to determine the concentration of the surfactant. Further, the mechanism of adhesion is elucidated.

Influence of nonionic surfactant on the solubilization and biodegradation of phenanthrene

Phenanthrene was solubilized in two different nonionic surfactants, Tween80 and Triton X-100. The bioavailability of phenanthrene to the bacteria isolated from the petroleum contaminated soils was studied based on the rotary flasks experiments. The results showed that the concentration of nonionic surfactants above the critical micelle concentration(CMC) can increase the solubility of phenanthrene in water and were innoxious to the phenanthrene-degrading bacteria; phenanthrene solubilized in the micelles of Tween80 was bioavailable and biodegradable. The research demonstrated the potential of surfactant-enhanced bioremediation of soils contaminated by hydrophobic organic compounds(HOCs).

Influence of Nonionic Surfactant Addition on Drag Reduction of Water Based Nanofluid in a Small Diameter Pipe

The goal of this research was to determine the impact of nonionic surfactants on drag reduction effect in water and metal oxide nanofluid. Two nonionic surfactants （Rokacet 07 and Rokanol KT） and copper（II） oxide wa- ter-based nanofluid were examined. Friction factors in a 4 mm diameter pipe for the Reynolds number between 8000 and 50000 were determined. Results showed that addition of nonionic surfactants caused the decrease of fric- tion factor in water and nanofluid. The drag reduction effect was similar in both cases. Presence of nanoparticles in the system has no great influence on drag reduction effect.

CALORIMETRIC STUDIES ON THE STRUCTURE OF MICROEMULSION WITH NONIONIC SURFACTANT

Enthalpic studies on the state of water in hex-adecane/hexanol/ AEO8/water system have been conducted. The results show that water exists in three states such as bound water,trap water and free water. The enthalpic effect of condition that water to oil ratio is in the abnormal rheology region, the negative thixotropy of the system is directly proportional to the enthalpy.

Formation of macroporous gel morphology by phase separation in the silica sol-gel system containing nonionic surfactant

The phase separation and gel formation behavior in an alkoxy-derived silica sol-gel system containing C16EO15 has been investigated. Various gel morphologies similar to other sol-gel systems containing organic additives were obtained by changing the preparation conditions. Micrometer-range interconnected porous gels were obtained by freezing transitional structures of phase separation in the sol-gel process. The dependence of the resulting gel morphology on several important reaction parameters such as the starting composition, reaction temperature and acid catalyst concentration was studied in detail. The experimental results indicate that the gel morphology is mainly determined by the time relation between the onset of phase separation and gel formation.

New Development of Reverse Micelles and Applications in Protein Separation and Refolding

Reverse micelles bring mild and effective microenvironments in organic solvent that contain bitmolecules, which have attracted immense attention for application in the isolation of proteins, protein refolding, and enzymatic reaction. In this review, the application of reverse micelles for protein separation and refolding has been briefly summarized and various reverse micellar systems composed of different surfactants, including ionic, non- ionic, mixed, and affinity-based reverse micelles, have been highlighted. It illustrates especially the potential application of the novel affinity-based reverse micelles consisting of biocompatible surfactant coupled with affinity ligands. Moreover, the importance to develop universal affinity-based reverse micelles for protein separation and refolding in the downstream processing of biotechnology has been pointed out.

Sorption of Triton X-100 on soil organic matter fractions:Kinetics and isotherms

Kinetics and isotherms of Triton X-100 sorption on soil,base-extracted soil（BE）,humic acid（HA） and humin（HM） were investigated respectively to get better understanding on characteristics of the surfactant sorption onto different soil organic matters（SOMs）.It was demonstrated that the kinetics results could be satisfactorily described by the pseudo-second order model.The half of the time to reach equilibrium（t1/2） for different sorbents followed the sequence of soil 〉 HA 〉 BE 〉 HM.Furthermore,the calculated equilibrium sorption capacity（Ceq） was found in the sequence of HA 〉 BE 〉 HM 〉 soil,which agreed well with the experimental results.The isotherms of Triton X-100 sorption on soil and HA could be well described by the S-type isotherm,but BE and HM by the L-type.The isotherms of all the four sorbents were found reasonably fitted to the Langmuir equation.The Kd value,defined as the ratio of Triton X-100 in sorbent and in the equilibrium solution for given concentrations,generally followed the order of HM 〉 HA 〉 soil 〉 BE.Separated HM and HA showed high affnity for Triton X-100,but the HA and HM in soil and BE were tightly bounded by the minerals.Thus,the HA on the soil surface might dominate the sorption,whereas the bounded HM would play a key role upon the surfactants being penetrated inside the soil.

Low-cost preparation of mesoporous silica with high pore volume

Mesoporous silica materials with high pore volume were successfully prepared by the chemical precipitation method, with water glass and a biodegradable nonionic surfactant polyethylene glycol （PEG）. The obtained materials were characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, thermo gravimetric analyzer and differential scanning calorimetry （TG-DSC）, nitrogen adsorption-desorption measurements, and X-ray diffraction （XRD）. The results showed that the changes of the pore parameters depended on both the surfactant content and heat treatment temperature. When the content of PEG was 10wt% and the obtained PEG/SiO2 composite was heated at 600℃, the mesoporous silica with a pore volume of 2.2 cma/g, a BET specific surface area of 361.55 m^2/g, and a diameter of 2-4 μm could be obtained. The obtained mesoporous silica materials have potential applications in the fields of paint and plastic, as thickening, reinforcing, and flatting agents.

The Effect of Adjuvants on Penetration of beta-cypermethrin Through the Epidermis of Cabbage Leaf

The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the penetration was positively correlated with both the concentration of adjuvant and the time after application, in a given range of treatment. A synergistic effect of two types of adjuvant on the penetration was found. Some physical properties of emulsions were determined. The change of the structures of the cabbage leaf surface by these adjuvants was observed from photomicrographs. The mechanism concerned with the effect of these adjuvants on the penetration of beta- cypermethrin through the cabbage leaf surface was tentatively discussed.

Effect of polyoxypropylene chain length on the critical micelle concentration of propylene oxide-ethylene oxide block copolymers

In this work, the surface activity of block copolymer nonionic surfactants (RPE) has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A), surface tension at CMC (γCMC). A linear decrease of ln[CMC] vs number of oxypropylene units in copolymer molecule was observed. The change in the work of cohesion per oxypropylene group when passing from molecular into micellar state, calculated from the Shinoda equation, was 0.43kT for the studied compounds.

Preparation and Characterization of In_2O_3 Nanorods

In_2O_3 nanorods were prepared by sol-gel technique with nonionic surfactant controlling their morphology,and were characterized by TEM,TG-DSC and XRD.The results indicated that In_2O_3 nanorods had the length of about 120 nm and diameter of 20 nm.The In_2O(OH)_4 dried gelatin was formed by partial dehydrating of In(OH)_3 molecules.The factors influencing the morphology of In_2O_3 nanorods and their growth mechanism were discussed.The geometry array parameter P of the nonionic surfactant was between 1/3～1/2 through calculation,which confirmed that the shape of the micelle was claviform.

Nonionic surfactant vesicular systems for effective drug delivery—an overview

Vesicular systems are a novel means of drug delivery that can enhance bioavailability of encapsulated drug and provide therapeutic activity in a controlled manner for a prolonged period of time.Liposomes were the first such system but they suffer from a number of drawbacks including high cost and lack of stability at various pHs.Niosomes are a nonionic surfactant vesicular system,which can be easily and reliably made in the laboratory.Many factors affect noisome formation such as the method of manufacture,nature of surfactant and encapsulated drug,temperature at which the lipids are hydrated and the critical packing parameter.This review describes all aspects of niosomes including their different compositions,the various methods of preparation,the effect of changing manufacturing parameters,methods of characterization,factors that affect their stability,their use by various routes of administration,their therapeutic applications and the most important patents.The review also provides detailed information of the various types of niosomes that provide effective drug delivery.

Drag-reduction of a nonionic surfactant aqueous solution and its rheological characteristics

In order to develop turbulent drag-reducing technology by using an environmentally friendly additive in a water-transporting system,the drag reducing characteristics in a non-ionic surfactant(Oleyldimethylamineoxide,ODMAO) dilute aqueous solution flowing in a circular pipe of 5 mm diameter have been experimentally investigated with an air-driven fluid resistance test device.The rheological characteristics of the solution have also been examined by a rheometer with a cone-plate flow cell.The results show that the ODMAO solutions are drag-reducing when concentration is 400 ppm or higher,that the critical Reynolds number corresponding to the maximum drag reduction rate increases with both concentration and temperature,and that the maximum drag reduction rate can reach up to 70% in the straight pipe.At low shear rates,the shear viscosity of ODMAO solutions with a relatively high drag-reduction behaves similarly to Newtonian fluids;at above a certain critical shear rate,it is firstly shear-thickening,then shear-thinning.Such shear-rate-dependent characteristics of the shear viscosity are attributed to the different transitions of micellar network structure induced by different shear rates.Relaxation of shear stress after removing an applied constant shear rate at which the solution is in the SIS(shear-induced structure) state is found to be well expressed by a 2-step Maxwell model with a tail relaxation time much shorter than that for a drag-reducing cationic surfactant,which indicates that for the ODMAO solution,a viscoelasticity as strong as a drag-reducing cationic surfactant is not needed to realize turbulent drag-reduction.

Catalytic Spectrophotometric Determination of Ultratrace Amounts of Silver with Solubilizing Effect of Nonionic Surfactant

The synthesis and analytical properties of 4,4'-bis(antipyrinyl-4-diazoamino)biphenyl (BAPDAB) were described for the first time. A catalytic kinetic method for thedetermination of silver was proposed. In the presence of Triton X-100 as a solubilizing agent and2,2'-dipyridyl as an activator, silver has a very strong catalytic effect on oxidative decolorationof BAPDAB by persulfate in acetic acid medium. The reaction was followed spectrophotometrically bymeasuring the decrease of absorbance of BAPDAB at 478 nm and 50 ℃. The calibration graphs are ofgood linearity in the range of 8.0 * 10^(-10)-1.0 * 10^(-6) mol/L by a fixed time method. The limitof detection is down to 5.0 * 10^(-10) mol/L. The catalytic reaction is pseudo-first-order withrespect to silver, which in real samples was determined with satisfactory results.