Nonpolar Surfactant Research Articles

Surface Defect Mitigation of Additively Manufactured Parts Using Surfactant-Mediated Electroless Nickel Coatings.

The emergence of defects during the early production phases of ferrous-alloy additively manufactured (AM) parts poses a serious threat to their versatility and adversely impacts their overall mechanical performance in industries ranging from aerospace engineering to medicine. Lack of fusion and gas entrapment during the manufacturing stages leads to increased surface roughness and porosities in the finished part. In this study, the efficacy of employing electroless nickel-boron (Ni-B) deposition to fill and level simulated AM defects was evaluated. The approach to levelling was inspired by the electrochemical deposition techniques used to fill vias in the electronics industry that (to some extent) resemble the size and shape of AM-type defects. This work investigated the use of surfactants to attenuate surface roughness in electroless nickel coatings, thereby achieving the preferential inhibition of the coating thickness on the surface and promoting the filling of the simulated defects. A cationic surfactant molecule, CTAB (cetyltrimethyl ammonium bromide), and a nonpolar surfactant, PEG (polyethylene glycol), at different concentrations were tested using a Ni-B electrolyte for the levelling study. It was found that the use of electroless Ni-B to fill simulated defects on ferrous alloys was strongly influenced by the concentration and nature of the surfactant. The highest levelling percentages were obtained for the heavy-molecular-weight PEG-mediated coatings at 1.2 g/L. The results suggest that electroless Ni-B deposition could be a novel and facile approach to filling defects in ferrous-based AM parts.

Structure, Partitioning, and transport behavior of microemulsion Electrolytes: Molecular dynamics and electrochemical study

Microemulsion electrolyte has been proposed as redox flow battery electrolyte to decouple the redox active species’ solubility and conductivity by taking advantage of stabilizing both aqueous and nonaqueous phases in nanoscale. Herein, molecular dynamic (MD) analysis was applied to characterize a family of Tween® 20/1-butanol/KNO3aq/Toluene microemulsions with different compositions, determining their microstructure that tends to adopt under standard conditions and evaluating their stability through total energy evolution. Instead of forming a densely packed surfactant layer that divides aqueous and nonaqueous phases, toluene was trapped in the nonpolar surfactant chain. Based on this finding, we proposed an alternative mathematical expression to correlate surface area-to-volume ratio with correlation length which provided a good accordance between simulation and experimental results. Moreover, the nature of the oil–water interface was revealed by quantitatively analyzing the hydrogen bonds between the surfactant/cosurfactant and the water. Electrochemical analyses are performed to examine how the structures of microemulsion electrolytes correlate to their electrochemical performance. The results indicate that absorption on the electrode surface, ionic conductivity, and connectivity of both aqueous and nonaqueous phases are of central significance in affecting the redox reaction. These findings, therefore, shed light on guiding the formulation of microemulsion electrolytes and regulating their electrochemical performance as electrolytes for redox flow battery applications. In the end, we proposed an electrochemical reaction mechanism of Fc in the microemulsion electrolyte.

Understanding the effects of polar and non-polar surfactants on the oxidation performance of copper nanoparticles

Understanding the effects of polar and non-polar surfactants on the oxidation performance of copper nanoparticles

Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material.

Despite all recent advances in medical treatments, infectious diseases remain dangerous. This has led to intensive scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well-established solution in this area. The present work studied the nucleation of silver on halloysite substrates modified by chemical treatment with NaOH. The resulting stabilized Ag-NPs were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The nucleation was characterized by thermogravimetric analysis and differential scanning calorimetry. The antimicrobial properties of the Ag-NPs were investigated against E. coli and S. aureus. The potential of the Ag-NPs for industrial application was tested by dispersing them into low-density polyethylene. The importance of the chemical affinity between matrix and additive was tested through coating the Ag-NPs with dodecanethiol, a non-polar surfactant. The resulting composites were characterized by scanning electron microscopy and in terms of surface antimicrobial activity. The results demonstrate that the Ag-NPs synthesized in this work are indeed antimicrobial, and that it is possible to imbue a polymeric matrix with the antimicrobial properties of Ag-NPs.

Effect of Polarity of Surfactant on Formation of through-Silicon Via Using Metal-Assisted Chemical Etching

In this study, we demonstrated formation of high aspect vertical holes in Si substrate using wet chemical approach, MacEtch process, for the application of through silicon via (TSV) holes. It is important that the addition of the surfactants in the etching solution to obtain the well- defined straight holes in the Si substrate using MacEtch, regardless the polarity of the surfactants. MacEtch is expected to be used for formation of TSV instead of Deep reactive ion etching (Deep-RIE) because of lower costs than Deep-RIE [1,2,3]. However, it is difficult to obtain high aspect vertical holes using MacEtch process due to its instability of etching direction for prolonged process as shown in Fig. 1(a). Addition of surfactant is usefulness to improve the morphology of etched holes. Micro scale holes were prepared in N-type Si (100) substrate using MacEtch process. The disc shape Au deposited by sputtering were used as catalyst. Before deposition of the Au catalyst, a Ti interlayer with a thickness of 10 nm was deposited directly on the Si substrate with patterned resist. The patterned Au discs (10 μm in diameter), which were deposited on a Ti / Si substrate using a photolithography lift-off process. The thicknesses of deposited Au were 10 nm for Ti/Si substrate. The base pressure of the deposition chamber was maintained at 10-5 Pa, and purity of Au and Ti target used for the deposition were 99.99 %, respectively. For the MacEtch process, a mixture of 1.0 M hydrofluoric acid (HF), 1.3 M hydrogen peroxide (H2O2) and deionized water was used as the base etching solution. Benzalkonium chloride (BKC), and polyethylene glycol (PEG), which were cationic and non-polar surfactant, respectively, were used as the additive for the etching solutions. The MacEtch of the Si substrate with patterned Au were performed for 120 min at 40 oC in the etching solution. Fig.1 shows cross sectional SEM images of typical shape of etched Si holes using MacEtch. The direction of etched Si hole was changed during MacEtch without surfactants, as shown Fig.1 (a), and these changes of direction occurred more than 60% Si holes. By contrast, we observed drastic improvement on direction of etched holes in almost all holes in addition of PEG, as indicated Fig.1 (b). Similarly, adding BKC in MacEtch process was also observed improvement. The catalyst at the bottom of substrate without surfactant was deformed and partially detached from the Si substrate, as shown Fig.1 (d). However, with PEG and BKC, the catalyst contacted to the bottom and was suppressed deformation, as indicated Fig.1 (e), (f). In addition, BKC suppressed at 25 times low concentration compared with PEG. This phenomenon was is considered due to influence of polarity of hydrogen part or structure of surfactants. Particularly, the shape of catalyst film with BKC kept flat during MacEtch process compared with PEG. Therefore, defamation of catalyst has a strong correlation with formation of bended holes. Moreover, the suppression effect of catalyst is stronger in cation, BKC, than in non-ion, PEG.

Experimental Study of Nonpolar Surfactant Mixed with Dielectric Fluid on Die-Sinking EDM of Ti-6Al-4V Alloy

Abstract This article deals with the study of the effect of nonpolar surfactant on the performance characteristics of Electrical Discharge Machining (EDM) of the Ti-6Al-4V alloy. The selected process parameters, like pulse on-time, pulse off-time, discharge current, and nonpolar surfactant concentration, and their effect on machining performance characteristics, like Thermal Conductivity (TC), Material Removal Rate (MRR), Surface Roughness (SR), Tool Wear Rate (TWR), and Recast Layer Thickness (RLT), were studied. In this article, the one-factor-at-a-time approach and Taguchi technique were used to determine the machining process parameters. Nonpolar surfactant is mixed into dielectric fluid, which increases the TC and suspends the debris particles in EDM oil to reduce the discontinued discharge conditions during machining. It was observed from the results that RLT, SR, and TWR are reduced, while MRR and TC are increased, compared to machining without nonpolar surfactant. Furthermore, the experimental results indicated that the surfactant was decomposed in EDM oil and that a small recast layer, which could be seen on migrated elements in EDX analysis peaks, formed on the machined surface.

Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces

Driven by the potential applications of ionic liquids (ILs) in many emerging electrochemical technologies, recent research efforts have been directed at understanding the complex ion ordering in these systems, to uncover novel energy storage mechanisms at IL-electrode interfaces. Here, we discover that surface-active ILs (SAILs), which contain amphiphilic structures inducing self-assembly, exhibit enhanced charge storage performance at electrified surfaces. Unlike conventional non-amphiphilic ILs, for which ion distribution is dominated by Coulombic interactions, SAILs exhibit significant and competing van der Waals interactions owing to the non-polar surfactant tails, leading to unusual interfacial ion distributions. We reveal that, at an intermediate degree of electrode polarization, SAILs display optimum performance, because the low-charge-density alkyl tails are effectively excluded from the electrode surfaces, whereas the formation of non-polar domains along the surface suppresses undesired overscreening effects. This work represents a crucial step towards understanding the unique interfacial behaviour and electrochemical properties of amphiphilic liquid systems showing long-range ordering, and offers insights into the design principles for high-energy-density electrolytes based on spontaneous self-assembly behaviour.

One-Pot Method for Preparation of Magnetic Multi-Core Nanocarriers for Drug Delivery.

The development of various magnetically-responsive nanostructures is of great importance in biomedicine. The controlled assembly of many small superparamagnetic nanocrystals into large multi-core clusters is needed for effective magnetic drug delivery. Here, we present a novel one-pot method for the preparation of multi-core clusters for drug delivery (i.e., magnetic nanocarriers). The method is based on hot homogenization of a hydrophobic phase containing a nonpolar surfactant into an aqueous phase, using ultrasonication. The solvent-free hydrophobic phase that contained tetradecan-1-ol, γ-Fe2O3 nanocrystals, orlistat, and surfactant was dispersed into a warm aqueous surfactant solution, with the formation of small droplets. Then, a pre-cooled aqueous phase was added for rapid cooling and the formation of solid magnetic nanocarriers. Two different nonpolar surfactants, polyethylene glycol dodecyl ether (B4) and our own N1,N1-dimethyl-N2-(tricosan-12-yl)ethane-1,2-diamine (SP11), were investigated for the preparation of MC-B4 and MC-SP11 magnetic nanocarriers, respectively. The nanocarriers formed were of spherical shape, with mean hydrodynamic sizes <160 nm, good colloidal stability, and high drug loading (7.65 wt.%). The MC-B4 nanocarriers showed prolonged drug release, while no drug release was seen for the MC-SP11 nanocarriers over the same time frame. Thus, the selection of a nonpolar surfactant for preparation of magnetic nanocarriers is crucial to enable drug release from nanocarrier.

Extracavity Effect in Cyclodextrin/Surfactant Complexation.

Cyclodextrin (CD) complexation is a convenient method to sequester surfactants in a controllable way, for example, during membrane-protein reconstitution. Interestingly, the equilibrium stability of CD/surfactant inclusion complexes increases with the length of the nonpolar surfactant chain even beyond the point where all hydrophobic contacts within the canonical CD cavity are saturated. To rationalize this observation, we have dissected the inclusion complexation equilibria of a structurally well-defined CD, that is, heptakis(2,6-di- O-methyl)-β-CD (DIMEB), and a homologous series of surfactants, namely, n-alkyl- N, N-dimethyl-3-ammonio-1-propanesulfonates (SB3- x) with chain lengths ranging from x = 8 to 14. Thermodynamic parameters obtained by isothermal titration calorimetry and structural insights derived from nuclear magnetic resonance spectroscopy and molecular dynamics simulations revealed that, upon inclusion, long-chain surfactants with x = ≥10 extend beyond the canonical CD cavity. This enables the formation of hydrophobic contacts between long surfactant chains and the extracavity parts of DIMEB, which make additional favorable contributions to the stability of the inclusion complex. These results explain the finding that the stability of CD/surfactant inclusion complexes monotonously increases with the surfactant chain length even for long chains that completely fill the canonical CD cavity.

Charging Mechanism for Polymer Particles in Nonpolar Surfactant Solutions: Influence of Polymer Type and Surface Functionality.

Surface charging phenomena in nonpolar dispersions are exploited in a wide range of industrial applications, but their mechanistic understanding lags far behind. We investigate the surface charging of a variety of polymer particles with different surface functionality in alkane solutions of a custom-synthesized and purified polyisobutylene succinimide (PIBS) polyamine surfactant and a related commercial surfactant mixture commonly used to control particle charge. We find that the observed electrophoretic particle mobility cannot be explained exclusively by donor-acceptor interactions between surface functional groups and surfactant polar moieties. Our results instead suggest an interplay of multiple charging pathways, which likely include the competitive adsorption of ions generated among inverse micelles in the solution bulk. We discuss possible factors affecting the competitive adsorption of micellar ions, such as the chemical nature of the particle bulk material and the size asymmetry between inverse micelles of opposite charge.

Characterizing the acid/base behavior of oil-soluble surfactants at the interface of nonpolar solvents with a polar phase.

We propose a simple method of characterizing the (Lewis) acid/base behavior of oil-soluble nonionic surfactants at the interface of nonpolar solvents with a polar phase. Using interfacial tensiometry, we probe the effective acidic and basic response of nonpolar surfactant solutions to contact with a variety of polar reference liquids. The measured interfacial tensions are used as experimental coefficients in a set of equations borrowed from the thermodynamic "surface energy component model" of van Oss, Chaudhury, and Good (vOCG), but used here in a more heuristic fashion and with a revised interpretation of the parameters extracted to describe the dispersive, acidic, and basic character of the sample. We test the proposed characterization method using alkane solutions of purified polyisobutylene succinimide (PIBS) surfactants with systematic structural variations, and observe that the inferred parameter values are consistent with, and sensitive to, subtle differences in the surfactant chemistry. This suggests the possibility to compare different surfactant solutions semiquantitatively with regard to their acidic and basic character. In a further illustration of the proposed analysis, we characterize a solution of commercial PIBS surfactant in hexane, and find that the parameters obtained by the proposed method correctly predict the solution interfacial tension with a polar liquid not included among the chosen reference liquids.

Characterizing generated charged inverse micelles with transient current measurements.

We investigate the generation of charged inverse micelles in nonpolar surfactant solutions relevant for applications such as electronic ink displays and liquid toners. When a voltage is applied across a thin layer of a nonpolar surfactant solution between planar electrodes, the generation of charged inverse micelles leads to a generation current. From current measurements it appears that such charged inverse micelles generated in the presence of an electric field behave differently compared to those present in equilibrium in the absence of a field. To examine the origin of this difference, transient current measurements in which the applied voltage is suddenly increased are used to measure the mobility and the amount of generated charged inverse micelles. The mobility and the corresponding hydrodynamic size are found to be similar to those of charged inverse micelles present in equilibrium, which indicates that other properties determine their different behavior. The amplitude and shape of the transient currents measured as a function of the surfactant concentration confirm that the charged inverse micelles are generated by bulk disproportionation. A theoretical model based on bulk disproportionation with simulations and analytical approximations is developed to analyze the experimental transient currents.

Effects of Trace Water on Charging of Silica Particles Dispersed in a Nonpolar Medium

This paper presents an investigation of the effects of trace water on the charging of silica (SiO(2)) particles dispersed in a nonpolar medium. There are a growing number of applications that seek to use electrostatic effects in apolar media to control particle movement and aggregation stability in such systems. One factor that is often overlooked in the preparation of nonpolar colloidal dispersions is the amount of water that is introduced to the system by hygroscopic particles and surfactants. The amount and location of this water can have significant effects on the electrical properties of these systems. For nonpolar surfactant solutions it has been shown that water can affect the conductivity, and it has been speculated that this is due to swelling of the polar cores of inverse micelles, increasing the fraction of them that are charged. Some studies have suggested that particle surface charging may also be sensitive to water content, but a clear mechanism for the process has not been fully developed. The situation with particles is further complicated by the fact that it is often unclear whether the water resides on the particle surfaces or in the polar cores of inverse micelles. The current work explores not only the effect of water content on reverse micelle and particle charging but seeks to differentiate between water bound to the particles and water located in the micelles. This is accomplished by measuring the solution conductivity and the electrophoretic mobility of silicon dioxide particles dispersed in solutions of Isopar-L and OLOA 11000. The water content is determined for both the dispersion and the supernatant after centrifuging the particles out. It is found that at equilibrium the majority of the water in the system adsorbs to the surface of the hygroscopic silica particles. In addition, the effect of water on particle electrophoretic mobility is found to be dependent on surfactant concentration. At small OLOA concentrations, additional water results in an increase in particle mobility due to increased particle charging. However, at large OLOA concentrations, additional water leads to a decrease in particle mobility, presumably as a result of increased electrostatic screening or neutralization. Thus, particle charging and electrophoretic mobility in an apolar surfactant solution are found to be highly sensitive to both the total water content in the system and to its concentration relative to the amount of surfactant present.

Pervaporation separation of organic azeotrope using poly(dimethyl siloxane)/clay nanocomposite membranes

The paper describes the preparation of poly(dimethyl siloxane) (PDMS)/clay nanocomposite membranes by in situ crosslinking of vinyl terminated PDMS (V-PDMS) resin in the presence of clay content varying from 1% w/w to 10% w/w in order to evaluate the influence of layered silicate on pervaporation characteristics of PDMS. Two commercial clays, Cloisite 30B and Nanomer 1.30P functionalized with polar and nonpolar surfactants were chosen for this purpose and PDMS membranes were prepared in the absence/or presence of varying amounts of different clays. Structural, mechanical and thermal characterization was done using Fourier transform infrared spectroscopy (FTIR), tensile testing system and thermogravimetric analyzer. Morphological characterization using X-ray diffraction and transmission electron microscopy showed intercalation or partial exfoliation of silicate layers. Surface characterization using scanning electron microscope showed an uniform dispersion of nanoclays in PDMS matrix. Two nanocomposite membranes having PDMS/nanoclay (10% w/w) were selected based on their mechanical properties and evaluated for their performance in separating azeotropic toluene/methanol mixture. Composite membranes showed higher selectivity as compared to neat PDMS and toluene was a preferred permeant. The total flux for composite membranes was lower as compared to PDMS membrane. This study demonstrates that polymer nanocomposite membranes could be an alternative way for tuning between permeation flux and selectivity in addition to enhanced thermal and mechanical properties.

Redox Transmetalation of Prickly Nickel Nanowires for Morphology Controlled Hierarchical Synthesis of Nickel/Gold Nanostructures for Enhanced Catalytic Activity and SERS Responsive Functional Material

A nonpolar surfactant assisted mild wet chemistry approach has been presented for controlled fabrication of ferromagnetic ultralong (several micrometers in length) prickly nickel nanowires in gram scale with the assistance of hydrazine hydrate as the reducing agent and nickel chloride as the metal ion precursor. Nanowire structures analogous to the natural plant Euphorbia milii resulted due to the magnetic dipole driven self-assembly, and their alignment was oriented desirably with an external magnetic field. Systematic microscopic characterizations identified the nanowire to be pure fcc-Ni (i.e., face-centered cubic Ni) without any signature of contamination, though X-ray photoelectron spectroscopy (XPS) and magnetization measurements refer to the existence of an ultrathin nickel oxide (NiO) layer over the nanostructures. The as-synthesized nanowires were used as a single-source precursor for the evolution of nanometric black NiO when calcined. Again, the Ni nanowires act as a sacrificial template that addresses deposition of metallic gold over the nanowire with variable structural hierarchy through their quantitative oxidative dissolution. Then, the composite material serves as a heterogeneous catalyst for reduction of 4-nitrophenol, and a probable reaction mechanism has been suggested. Additionally, the materials were proved to furnish a full-proof enhanced field effect for prolific surface-enhanced Raman scattering (SERS) activity. In a nutshell, the strategy provides a new horizon to design need-based functional material with much practical implication.

Effect of EVA as compatibilizer on the mechanical properties, permeability characteristics, lamellae orientation, and long period of blown films of HDPE/clay nanocomposites

AbstractTwo ethylene‐vinyl acetate (EVA) resins with 19% (EVA19) and 28% (EVA28) of vinyl groups were used as compatibilizers for nanocomposites of high‐density polyethylene (HDPE) and nanoclays. Two nanoclays were also used, one with a nonpolar surfactant (C15A) and another with a polar surfactant (C30B). The HDPE/EVA19/C15A formed an intercalated structure, while the HDPE/EVA28/C30B had surfactant loss. Blown films of these compositions were produced. A two‐phase morphology made of HDPE and EVA/nanoclay particles was observed, which was responsible for the increase in water vapor and oxygen permeability rates of the films. The elastic modulus E along the transverse direction of the films was higher than along the machine direction due to preserved orientation given by the spiral die; the lamellae orientation was measured by small‐angle X‐rays diffraction. The highest E was observed in the HDPE/EVA19/C15A film due to stronger interactions. The long period of the HDPE lamellas was not affected by the presence of the EVA and nanoclay. A model was proposed to explain the improvement in elastic modulus due to the processing conditions and components' interactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Thermoplastic Olefin/Clay Nanocomposites. Effect of Matrix Composition, and Organoclay and Compatibilizer Structure on Morphology/Properties Relationships

The effect of different nanofillers and compatibilizers (maleic anhydride-grafted-polypropylene and maleic anhydride-grafted-ethylene propylene diene terpolymer rubber) on the morphology, mechanical, mechanodynamical and thermal characteristics of thermoplastic olefins based on polypropylene and ethylene propylene diene terpolymer rubber blends has been analysed. A better affinity with the matrix and a better dispersion of the nanoparticles is observed in rubber rich matrices. Organoclay, such as Cloisite C15A and Cloisite C20A, treated with a non-polar surfactant give rise to intercalated nanocomposites, and the lower the concentration of surfactant (C20A) the most noticeable increase in interlayer spacing and consequently better properties in the nanocomposites. The maleic anhydride-grafted-ethylene propylene diene terpolymer rubber is a better compatibilizer for organo-clay nanocomposites based on rubber rich matrices.

Dispersion characteristics and rheology of organoclay nanocomposites based on a segmented main-chain liquid-crystalline polymer having side-chain azopyridine with flexible spacer

The dispersion characteristics and rheology of organoclay nanocomposites based on a main-chain liquid-crystalline polymer having side-chain azopyridine with flexible spacer (PABP) were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and oscillatory shear rheometry. In the preparation of nanocomposites via solution blending under vigorous stirring, two commercial organoclays (Southern Clay Products) were employed: one (Cloisite 30B) treated with a surfactant (MT2EtOH) having hydroxyl groups, and the other (Cloisite 20A) treated with a nonpolar surfactant (2M2HT) having hydrogenated tallow. Also prepared, for comparison, were nanocomposites prepared by mixing PABP with natural clay (montmorillonite, MMT). The following observations were made. (i) PABP/Cloisite 30B nanocomposite has featureless XRD patterns and a very high degree of dispersion of Cloisite 30B aggregates as determined from TEM. (ii) PABP/Cloisite 20A nanocomposite has shown a conspicuous XRD reflection peak and intercalation of Cloisite 20A aggregates as determined from TEM. (iii) PABP/MMT nanocomposite has shown XRD patterns, which are virtually the same as the XRD patterns of neat PABP with a slightly increased gallery distance, and it has very poor dispersion of MMT aggregates in the matrix of PABP. The observed high degree of dispersion of Cloisite 30B aggregates in PABP/Cloisite 30B nanocomposite is attributable to the formation of hydrogen bonds between the pyridyl group of side-chain azopyridine and the hydroxyl groups in the surfactant MT2EtOH residing at the surface of Cloisite 30B. The presence of hydrogen bonds in the PABP/Cloisite 30B nanocomposite was confirmed by in situ Fourier transform infrared (FTIR) spectroscopy. It was observed via polarized optical microscopy that the liquid crystallinity of PABP in the PABP/Cloisite 30B nanocomposites was more or less intact with a very high degree of dispersion of Cloisite 30B aggregates. Oscillatory shear flow measurements of the organoclay nanocomposites prepared support the conclusions drawn from XRD, TEM, and FTIR spectroscopy.

Time-of-flight secondary ion mass spectrometry analysis of the application of a cationic conditioner to 'clean' hair

In this study the applicability of the surface-sensitive ToF-SIMS technique to hair analysis and associated aqueous processing is evaluated. ToF-SIMS analysis of "as received" human hair indicates the presence of silicones, anionic surfactants, and cationic conditioners, from previous treatments, on the fiber surface. Cleaning of the hair with SLS or SLES results in adsorption of the surfactants onto the fiber surface. In particular, the more non-polar surfactant components have greater substantivity for the fiber surface, as indicated by the relative increase in their ToF-SIMS intensity. Application of the Incroquat Behenyl 18-MEA conditioner to both "virgin" and bleached hair results in the adsorption of the cationic C18, C20, C22, and C21 surfactant components onto the hair surface. The ToF-SIMS data indicate higher levels of conditioner on the bleached hair relative to the undamaged hair.

The Effects of a Non-polar Surfactant on the Crystallization Behavior and Physical Properties of the High-Melting Triglyceride Fraction of Milkfat

The Effects of a Non-polar Surfactant on the Crystallization Behavior and Physical Properties of the High-Melting Triglyceride Fraction of Milkfat