Influence of Ionic Surfactants on the Properties of Nanoemulsions Emulsified by Nonionic Surfactants Span 80/Tween 80

The instability of nanoemulsions were mainly due to Ostwald ripening. The droplet charge was influenced by the stability of nanoemulsions significantly. In this work, the properties of the shea butter oil-loaded nanoemulsions were investigated in detail with the addition of cationic surfactants (cetyl trimethyl ammonium chloride, 1631; octadecyl trimethyl ammonium chloride, 1831), anionic surfactants (alcohol ethoxysulfate, AES; dodecyl phosphate ester sodium salt, MAP), and zwitterionic surfactants (cocoamidopropyl betaine, CAB; dodecyl hydroxysulfobetaine, 20HD). By increasing the concentration of cationic surfactants, the positively charged nanoemulsions were prepared and the smallest droplets were being formed with 0.05% 1831. Upon the addition of anionic surfactants, a more negative value was obtained and the smallest droplets were being formed with 0.1% AES. The ionic surfactants by increasing the electrostatic interactions between droplets and incorporation into the oil phase improved the stability of the nanoemulsions via lowering the Ostwald ripening rate, and especially improved the high temperature stability. By increasing the concentration of zwitterionic surfactants, a less negative zeta potential was observed and the stability of the nanoemulsions did not improve. The results proved that the electrosteric repulsion had an appreciable impact on the stability of the nanoemulsions.     

卵清蛋白与离子型表面活性剂的相互作用

本文通过荧光光谱法、紫外-可见吸收光谱法和透射电镜并结合电导率测定分别研究了水中卵清蛋白与阴离子表面活性剂十二烷基硫酸钠（SDS）和阳离子表面活性剂十二烷基三甲基溴化铵（DTAB）和十六烷基三甲基溴化铵（CTAB）之间的相互作用。研究结果表明卵清蛋白可以增加SDS和CTAB的临界胶束浓度,但对DTAB的临界胶束浓度没有影响。阴离子表面活性剂可以使卵清蛋白构象完全伸展,而阳离子表面活性剂却不具备此种作用。表面活性剂单体与卵清蛋白的相互作用强于表面活性剂胶束与卵清蛋白的相互作用。     

How Nano-Ions Act Like Ionic Surfactants

Recently, nanometric ions were shown to adsorb to hydrated neutral surfaces and to bind to the cavities of macrocyclic molecules with an unexpectedly strong affinity arising from a solvent-mediated effect named superchaotropicity. We show here that nano-ions at low concentrations (μm range), similarly to anionic surfactants, induce the spontaneous transformation of a swollen lyotropic lamellar phase of non-ionic surfactant into a vesicle phase. This transition occurs when the neutral lamellae acquire charges, either by adsorption of the nano-ions onto, or by anchoring of the ionic surfactant into the lamellae. In contrast to ionic surfactants, nano-ions strongly dehydrate the neutral surfactant assemblies. As a conclusion, these purely inorganic nanometric ions act as alternatives to the widely used organic ionic surfactants.     

Ionic Complexes of Polyacids and Cationic Surfactants

Comb-like ionic complexes were prepared from polyuronic acids (pectinic and alginic acids) and alkyltrimethylammonium surfactants bearing linear alkyl chains with 18, 20 and 22 carbon atoms. In the condensed state, these complexes were able to self-assemble in ordered structures which were thermally stable up to ∼200 °C. The complexes were analysed by DSC and WAXS/SAXS and compared to their analogous made from poly(γ-glutamic acid). They all adopt a biphasic layered structure in which the main chain and the alkyl side chain alternate with a nanometric periodicity. Alkyl side chains were partially crystallized in these complexes and they show reversible melting at temperatures within the 60-80 °C range depending on the length of the polymethylene segment.     

Effects of Metal Ions on the Micellization of Ionic Surfactants

The effect of metal ions (Cu(II), Zn(II), Co(II), Ni(II), La(III), Fe(III)) on the critical micelle concentration (CMC) of ionic surfactants (sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB)) were investigated at 25±0.1°C, μ = 0.1 M (KNO₃), using conductivity method in this paper. A series of general empirical expressions about the relationship between the CMC values for SDS and CTAB and the concentrations of metal ions have been derived. The results showed that the CMC values for both SDS and CTAB decreased with increasing the concentrations of metal ions. This can be interpreted by the counterion effect and the entropy driving effect.     

Ionic Complexes of Biotechnological Polyacids with Cationic Surfactants

Summary: Stoichiometric complexes of biotechnological poly(γ-glutamic) acid and poly(β,L -malic) acid with alkyltrimethylammonium surfactants of long alkyl chains could be readily prepared in aqueous medium. They adopt a biphasic layered structures in which the main chain and the side chain alternate with nanometric periodicity. Alkyl side chains show reversible melting that involves generation of mesophases. Complexes degraded by water by different mechanisms depending on the constitution of the main chain; the polymalic complexes underwent surface erosion whereas the polyglutamic ones degraded in bulk. Erythromycin could be homogenously loaded into the paraffinic subphase of the complexes and delivered upon incubation under physiological conditions in parallel to the hydrolysis of the polymer.     

The Interaction between High-Molecular-Weight Flocculents and Ionic Surfactants

The interaction between the anionic and cationic polyelectrolytes of various molecular masses and charges and the ionic surfactants in aqueous and salt solutions is studied by viscometry, conductometry, light scattering, and electrophoresis. Oppositely charged molecules of surfactant and polymer form strong complexes due to the forces of electrostatic attraction that is manifested in a significant decrease in the viscosity and light transmission, as well as in the relative reduction in solution conductivity. As the surfactant/polyelectrolyte ratio increases, the forming complexes precipitated and then dissolved again. In the case of strongly charged polyelectrolytes, the partial dissolution of precipitates was observed preceding the wide region of destabilization. In this region, the value of surfactant/polyelectrolyte charge ratio reaches 3–4. The interaction between the cationic surfactants and anionic polyelectrolyte increases with the lengthening of alkyl radical, thus indicating the presence of cooperative interactions between the surfactant molecules bonded to polymer and the important role of relevant hydrophobic interactions. As a result, the interaction between the high-molecular-weight anionic polyelectrolytes and anionic surfactants containing aromatic core takes place in some cases.     

Interaction of Nonionic Surfactant Triton-X-100 with Ionic Surfactants

The interaction in two mixtures of a nonionic surfactant Triton-X-100 (TX-100) and different ionic surfactants was investigated. The two mixtures were TX-100/sodium dodecyl sulfate (SDS) and TX-100/cetyltrimethylammonium bromide (CTAB) at molar fraction of TX-100, α_TX-100 = 0.6. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γ_CMC), maximum surface excess concentration (Γ_max), and minimum area per molecule at the air/solution interface (A _min) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were also determined. Mixtures of both TX-100/SDS and TX-100/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.     

How Nano‐Ions Act Like Ionic Surfactants

Recently, nanometric ions were shown to adsorb to hydrated neutral surfaces and to bind to the cavities of macrocyclic molecules with an unexpectedly strong affinity arising from a solvent‐mediated effect named superchaotropicity. We show here that nano‐ions at low concentrations (μm range), similarly to anionic surfactants, induce the spontaneous transformation of a swollen lyotropic lamellar phase of non‐ionic surfactant into a vesicle phase. This transition occurs when the neutral lamellae acquire charges, either by adsorption of the nano‐ions onto, or by anchoring of the ionic surfactant into the lamellae. In contrast to ionic surfactants, nano‐ions strongly dehydrate the neutral surfactant assemblies. As a conclusion, these purely inorganic nanometric ions act as alternatives to the widely used organic ionic surfactants.     

Interaction of Ionic Surfactants with a Hydrophobic Modified Thermosensitive Polymer

The interactions of a hydrophobic modified thermosensitive polymer poly(N-isopropylacrylamide)-ran-poly(methacrylic acid)-ran-poly(octadecyl acrylate) with five ionic surfactants, namely, sodium dodecyl sulfate (SDS), dodecayltrimethylaminium bromide (DTAB), 1,2-bis(dodecyldimethylammonio)- hexane dibromide (12-6-12), 1-dodecanaminium, N,N′-[(1,4-dioxo-1,4-butanediyl) bis(oxy-2,1-ethanediyl)] bis[N,N-dimethyl-, bromide] (12-su-12), and dodecanaminium, N, N′-[[(2E)-1,4-dioxo-2-butene-1, 4-diyl]bis(o-xy-2,1ethanediy-l)] bis[N,N-dimethyl-, bromide] (12-fo-12) were investigated by the static-steady fluorescence methods using crystal violet and pyrene as the probes. It was found that the SDS interacted with the polymer driven by the hydrophobic interaction, while the cationic surfactants first entered the core of the polymer micelle through the hydrophobic interaction then the corona area of the polymer micelle through the hydrophobic and static electrical interactions. Measurements of the transmittances of the polymer/surfactants/PBS mixtures at different temperatures showed that the SDS suppressed the phase transition of the system, while additions of the cationic surfactants into the polymer induced the phase transitions of the polymer complex systems first, then suppressed them after the minimum values of the lower critical phase transition temperatures (LPTT) was reached. It was also found that increase of the MAA content in the polymer could broaden the LPTT range adjusted by the cationic surfactants.      

Effect of Surfactants and Ionic Strength on Dissociation of Hydrochlorides of Phenothiazine Derivatives

Abstract

A study of the effect of the anionic surfactant dodecyl sulfate, the cationic surfactant carbethoxypentadecyl trimethyl ammonium bromide (Septonex), nonionic surfactant p-octyl phenyl polyoxyethylene (Triton X-100), and a strong electrolyte (KBr) on the dissociation of the hydrochlorides of two derivatives of phenothiazine (diethazine and fluphenazine) was made. It was found that sodium dodecyl sulfate increases the pKa value, whereas Septonex and Triton X-100 decrease this value. The presence of KBr suppresses the effect of the surfactants. A new method for the potentiometric determination of fluphenazine in an aqueous medium was proposed.     

Adsorption and Recovery of Ionic Surfactants by β-Cyclodextrin Polymer

The adsorption and recovery of ionic surfactants, such as dodecylbenzenesulfonic acid (DBS) and benzalkonium chloride (BKC), from an aqueous solution were studied using the β-cyclodextrin polymer (β-CDP). BKC always demonstrated a higher adsorption efficiency than DBS in batch tests, isotherms, and column tests. The adsorption characteristics of the surfactants seemed to be caused by inclusion into β-CD, and they were easily determined using the Langmuir adsorption isotherm. Furthermore, the surfactants adsorbed by β-CDP were easily released by shaking it with a mixture of water and methanol. Recovery efficiency was dependent on the mixture ratio of the solvent, and regenerated β-CDP was reusable as an adsorbent.     

Solubility of LIDOCAINE in Ionic, Nonionic and Zwitterionic Surfactants

The solubility of an anesthetic drug, LIDOCAINE, in water was investigated in the presence of ionic, nonionic and zwitterionic surfactants at 25 °C, and the solubility was found to increase linearly with the surfactant concentration. The molar solubilization ratio, R _m,s, and Gibbs free energy, DG_s^o\Delta G_{\mathrm{s}}^{\mathrm{o}} values for nonionic surfactants fall in the order DDAO > Brij 35 > Brij 30, whereas for ionic and zwitterionic surfactants the order is DDAPS > DTAB > SDS. The high negative values of the Gibbs energies in the cases of DDAO and DDAPS prove them to be better surfactants for solubilizing this drug as compared to the other surfactants.     

A Synergistic Effect of Select Organotin Compounds and Ionic Surfactants on Liposome Membranes

Organometallic compounds and surfactants constitute a potential threat to the environment. For that reason we have embarked on a study of their joint action on membranes. Model lecithin liposome membranes were modified with the cationic surfactant trimethyldodecylammonium bromide or the anionic surfactant sodium dodecylsulfonate, and the effect of tripropyltin chloride on the process of calcium (Ca²⁺) and praseodymium (Pr³⁺) desorption from the liposome membrane was studied. Kinetic constants for the process of Ca²⁺ ion desorption from lecithin liposome membranes were determined using the radiotracer method. The percentage of Pr³⁺ ion desorption from liposome membranes was measured by the ¹H NMR method. Trimethyltin, triethyltin and tripropyltin alone caused increased Ca²⁺ and Pr³⁺ desorption from liposome membranes with increasing concentration of the compounds and alkyl chain length. For both the processes studied, a cationic surfactant brought about a lower effectiveness of tripropyltin and an anionic surfactant resulted in a higher effectiveness. The effect observed can be explained by changes in the surface charge of the membrane, induced by the surfactant modifiers and by the concomitant change in the partition coefficient of the organotin. The results obtained indicate a protective or harmful joint action of the surfactants used with tripropyltin on membranes. © 1997 John Wiley & Sons, Ltd.     

表面活性剂体系中电荷诱导的层状相向囊泡相的转化

向一种非离子表面活性剂LA070(英文名AlcoholC12-C16Poly(1-6)Ethoxylate)复配体系LA070/C8H17OH/H2O形成的层状相中加入离子型表面活性剂使其电荷化,在电荷诱导下,双分子层的曲率发生变化,闭合形成具有黏弹性的囊泡相.离子型表面活性剂的加入量增大到一定程度时,由于反离子的屏蔽作用,囊泡结构被破坏,溶液的黏弹性消失,澄清的溶液逐渐变混浊,然后分为两相.     

Reversed-Phase HPLC. Determination of Ionic Surfactants As UV-Absorbing Ion Pairs

Abstract

Ionic and amphoteric surfactants were separated on reversed-phase columns. Ultraviolet photometry and differential refractometry were employed so that ion pairing and nonpairing compounds could be distinguished. Analysis of ionic surfactants as ultraviolet (UV) absorbing ion pairs improved detection limits 100 fold compared to detection by differential refractometer (RI).     

Interaction of PEO-PS-PEO Block Copolymers with Ionic Surfactants in Aqueous Solution

Abstract

The formation of polyelectrolyte type complex by the interaction between ionic (anionic and cationic) surfactant and block copolymer in water was observed from viscosity measurements. Interaction between the two was also examined from conductance and surface tension measurements were two transitions, one below and one above the critical micelle concentration, CMC, of the surfactants were observed. A possible mechanism for such an interaction is proposed.     

不同电荷基团修饰环糊精与离子型表面活性剂的键合行为研究

采用紫外-可见光谱和荧光光谱滴定的方法测定了单(6-脱氧-6-苯胺)-β-环糊精(1)、单(6-脱氧-6-乙二胺-β-环糊精(2)和单[6-氧-(4-苯甲酸)β-环糊精(3)在磷酸缓冲溶液中分别与阴离子表面活性剂十二烷基硫酸钠(SDS)和阳离子表面活性剂十二烷基三甲基溴化铵(DTAC)包结配位的稳定常数,并通过二维核磁等手段研究了主-客体之间的键合模式.结果表明,在环糊精的小口端修饰带有不同电荷的取代基,引入静电相互作用的识别位点,能够有效地改变环糊精对于离子型表面活性剂的键合能力,从而实现主体环糊精对于客体分子的选择性识别.