Surfactant Chain Research Articles

Controlled recombination rate of lophyl radicals in cationic surfactant micelles

In this study, we aimed to control the recombination rate of lophyl radicals in micelles, which were produced from a lophine dimer by ultraviolet irradiation, formed by cationic surfactants with different alkyl chain lengths. The recombination rate in the micellar solution of the surfactant with a shorter alkyl chain was enhanced compared to that with a longer alkyl chain. Small-angle neutron scattering measurements showed that mixtures of the cationic surfactant and the lophine dimer derivative formed elliptical micelles, and a smaller inner volume was observed when shorter chain surfactants were used. Furthermore, evaluation of the kinetic parameters indicated that the randomness of the lophyl radical in the shorter surfactant micelle was higher than that in the longer surfactant micelle. These results revealed that the size of the confined space formed by the micelles determines the recombination rate of the lophyl radicals. This provides a new methodology for the development of volatile and nonvolatile molecular memories with arbitrary retention times and future quantum computing based on photochromic compounds.

Influence of dodecyl surfactants on the cross-linking, plasticization and damping behavior of epoxy novolac resins.

A series of modified epoxy novolac resins (ENRs) were prepared by incorporating dodecyl chain surfactants with polar groups such as amine, carboxylic acid, phenol, resorcinol and benzene sulfonic acid. Except for the case of benzene sulfonic acid, no macrophase separation is seen in any of the modified ENRs. The addition of these dodecyl surfactants to ENR hinders the cross-linking reaction as revealed from their dynamic and isothermal DSC curing measurements and reduced glass transition temperatures (Tg). The cross-link density evaluated from the storage modulus (E') in the rubbery region using DMTA measurements is found to be low with the addition of surfactants in agreement with their plasticization behavior. The stiffness of the materials obtained at low temperatures showed a moderate increase for ENRs with carboxylic acid and phenol surfactants. Upon heating, their storage modulus drops at low temperatures compared to ENR supporting the mechanism of plasticization in them. This high value of E' for the plasticized material in the glassy phase is different from the generally known behavior. Such unusually high storage modulus together with increased 'd' spacing from the XRD results seems to indicate 'partial segmental confinement' of epoxy chains. It is believed that high damping obtained in these two materials is due to 'partial segmental confinement' of epoxy chains because of interaction with lauric acid and phenolic surfactants and the associated internal and interfacial friction in them. Dielectric relaxation measurements support the plasticization process based on the high dielectric loss and ionic conductivity in the surfactant modified ENR, as compared to the pristine ones.

Stabilization of CO2-foams in brine by reducing drainage and coarsening using alkyldimethylamine oxides as surfactants

Producing CO2-foams in saline environments can be a great challenge in many industrial applications, since fast gas diffusion and reduction of electrical double layer promote fast coarsening and coalescence of bubbles. Amine oxides are zwitterionic surfactants that have been shown to improve foam stability by intermolecular hydrogen bonding, but have not been investigated for CO2-foams yet. This paper reports a study on the use of commercial alkyldimethylamine oxides (CxDAO) as foaming agents in brine for CO2-foams, based on the interactions present at the low pH imposed by the dissolution of the CO2 and the presence of salts. Despite the presence of salt and CO2 increased the protonation degree of amine oxide molecules, favoring hydrogen bonding, a significant improvement in foam stability was only observed when using the long chain surfactant (C14DAO). This behavior was attributed to the synergy between increased attractive hydrophobic interactions of alkyl chains and reduced repulsion among ionic surfactant heads, which led to formation of large surfactant aggregates in bulk, as demonstrated by the significant increase in viscosity of the aqueous phase. There was also a decrease in foam drainage and coarsening rates for the foams using C14DAO in brine, compared to results in deionized water, suggesting that formation of hydrogen bonds is not enough to arrest the destabilization in CO2-foams. Moreover, the linear rate of bubble growth obtained for these foams (∝t) was higher than that reported for N2– or air-foams (∝t1/2), likely due to the high solubility of CO2 in the aqueous phase, which accelerated the coarsening phenomena. The results of this work offer insight on the future design of foaming formulations for stabilizing CO2-foams in applications that require the use of high salinity brines, such as carbon sequestration and oil recovery.

Single-Molecule Interactions at a Surfactant-Modified H2 Surface Nanobubble.

In schematics and cartoons, the gas-liquid interface is often drawn as solid lines that aid in distinguishing the separation of the two phases. However, on the molecular level, the structure, shape, and size of the gas-liquid interface remain elusive. Furthermore, the interactions of molecules at gas-liquid interfaces must be considered in various contexts, including atmospheric chemical reactions, wettability of surfaces, and numerous other relevant phenomena. Hence, understanding the structure and interactions of molecules at the gas-liquid interface is critical for further improving technologies that operate between the two phases. Electrochemically generated surface nanobubbles provide a stable, reproducible, and high-throughput platform for the generation of a nanoscale gas-liquid boundary. We use total internal reflection fluorescence microscopy to image single-fluorophore labeling of surface nanobubbles in the presence of a surfactant. The accumulation of a surfactant on the nanobubble surface changes the interfacial properties of the gas-liquid interface. The single-molecule approach reveals that the fluorophore adsorption and residence lifetime at the interface is greatly impacted by the charge of the surfactant layer at the bubble surface. We demonstrate that the fluorescence readout is either short- or long-lived depending on the repulsive or attractive environment, respectively, between fluorophores and surfactants. Additionally, we investigated the effect of surfactant chain length and salt type and concentration on the fluorophore lifetime at the nanobubble surface.

Interfacial properties of nonionic hybrid surfactant with double branches of fluorocarbon and hydrocarbon

To obtain superior surface-active properties while minimizing environmental risks, new fluorinated surfactants (F2HX-nEO) were designed to include a hybrid multi-chain with a short fluorocarbon (–CF2CF3) and nonionic ethylene oxide. They were simply synthesized by a straightforward reaction involving the addition of ethylene oxide to a hybrid fluorine alcohol, and their surface-active properties were optimized by controlling the hydrocarbon length and number of ethylene oxide units. Therefore, the desirable values of critical micelle concentration (0.3 mmol/L) and surface tension (24.3 mN/m) were obtained in spite of containing the short fluorocarbon chain. Particularly, F2HX–nEO showed excellent wetting properties on hydrophobic surfaces and very low toxicity level, which can be used in various fields as a promising alternative to long fluoroalkyl chain surfactants.

Some new phospho-zwitterionic Gemini surfactants as corrosion inhibitors for carbon steel in 1.0 M HCl solution

Three anionic–cationic phospho-surfactant candidates were prepared and tested as corrosion inhibitors against carbon steel corrosion in 1.0 M aggressive HCl medium. They having a different carbon chain tails ZGO (8 carbons), ZGD (12 carbons) and ZGH (16 carbons). This studying consider the first that handle these new surfactant category as corrosion inhibitors. The corrosion process has been studied gravimetrically & electrochemically. The atomic force microscope (AFM) & X-ray photoelectron spectroscopy (XPS) clarified the adsorption of the prepared anionic–cationic phospho-zwitterionic surfactant on the steel surface. The surfactant tail showed a significant impact on the corrosion protection process. Increasing the surfactant tail length led to improving the corrosion inhibition efficiency, which mainly ascribed to the higher adsorption affinity of longer chain surfactant. The ZGH surfactant showed highest inhibition efficiency 91.1% compared to other candidates with shorter chain length. The results confirmed enhancing the inhibition efficiency as function of increasing the temperature up to 70 °C, implying the preferably induced chemical adsorption by these phospho-based surfactants. The maximum inhibition efficiency has been achieved at 70 °C, for all synthesized phospho-surfactants following Langmuir adsorption isotherm with chemical adsorption predication as the adsorption free energy ranges from −63.4 to −75.2 kJ/mol. The electrochemical Tafel clarified that the ZGO, ZGD, & ZGH behave as mixed-type inhibitors. • New phospho-zwitterionic Gemini surfactant showed good corrosion inhibition performance for first time study. • The synthesized inhibitors behaves as mixed type inhibitors as clarified from the Tafel response. • The adsorption of ZGO, ZGD, and ZGH obey Langmuir isotherm. • The inhibition efficiency ordered as ZGH > ZGD > ZGO based on increasing the hydrophobicity. • The AFM and XPS confirmed the effective adsorption of ZGO, ZGD and ZGH inhibitors.

A systematic research on spontaneous imbibition of surfactant solutions for low permeability sandstone reservoirs

Surfactants, which possess ability to alter rock surface wettability and reduce interfacial tension (IFT), are effective additives for imbibition enhanced oil recovery (IEOR) in low sandstone permeability reservoirs. However, the imbibition efficiencies vary from different surfactants, and some surfactants even have a negative effect on IEOR. Thus, it is necessary to research optimum surfactants suitable for IEOR. Considering that the surfactant properties are closely related to its molecular structure, this study systematically investigated the static imbibition efficiencies of different surfactants based on molecular structures, which contain different surfactant types, ionic head groups, hydrophilicity, and carbon chain lengths. In addition, the imbibition performance of surfactant solutions with different IFTs were also researched. The imbibition tests were conducted with Amott cells at 80 °C, using Changqing low permeability outcrop sandstones. Subsequently, IFT tests, viscosity measurements, contact angle (CA) measurements, and zeta potential tests were conducted to explore the IEOR mechanisms of different surfactant solutions. The experimental results showed that the IEOR potential of different types of surfactants was: anionic > nonionic > brine > amphoteric > cationic. Sulfate anionic surfactants showed better ability of wettability alteration than sulfonate surfactants, and achieved the most imbibition efficiency. Increasing the hydrophilicity of surfactants by introducing the ethylene oxide (EO) groups to the surfactant structures was effective in enhancing wettability alteration ability of surfactants and improving imbibition recovery. Surfactants with longer carbon chain (C16 surfactants) enhanced more imbibition recovery than short carbon chain surfactants (C12 surfactants), which was mainly depending on better IFT reduction ability of C16 surfactants than C12 surfactants. Appropriate IFT reduction, such as 10−1 mN/m levels, which reduced the adhesion work, enhanced the gravity dominated imbibition and avoided too much capillary pressure reduction, was the most desirable for IEOR. Too low IFTs, such as less than 10−2 mN/m, were not suitable for IEOR, because the capillary pressure reduced greatly, resulting in the imbibition process mainly dominated by gravity. This study provides fundamental information about the selection and design of surfactants for IEOR in low sandstone permeability reservoirs.

Controlling effect of hydroxyl phenyl aminopropyl cationic surfactants on the catalytic and biological performance of AgNPs

Three Hydroxy phenyl aminopropyl cationic surfactants with different carbon tail length; 8 (HPAPO), 12 (HPAPD), and 16 (HPAPH) have been synthesized successfully. The hydrophobic tail showed a pivotal impact on the morphological structure of the prepared silver nanoparticles (AgNPs) in terms of particles size, stability and yields as confirmed by TEM, DLS and UV-Vis spectroscopy measurements. The prepared AgNPs by HPAPH surfactant has a uniform structure with smaller particles size, and higher stability compared to that prepared by shorter chain length surfactants HPAPO and HPAPD. The HPAPH surfactant lead to formation AgNPs with size 12.9 ± 3.5 nm with high zeta potential 75.9± 6.4 mV indicating for highest stability. The surface and thermodynamic properties of the HPAPO, HPAPD and HPAPH surfactants are dependent on temperature and the hydrophobic tail length. The adsorption affinity is enhanced as temperature or chain length is increased. Increasing the surfactant hydrophobic tail or the solution temperature lead to decreasing the critical micelle concentration (CMC) of the surfactant solution. The hydrophobic chain exhibited a significant impact on the catalytic activity of the AgNPs toward removal some toxic pollutants such as methylene blue (MB) and p-nitrophenol (p-NP). The synthesized AgNPs using longer surfactant tail (HPAPH/AgNPs) showed highest catalytic activity compared to that prepared via shorter chain, which consider a promising study in terms of surfactant chain influence on the catalytic performance. The prepared cationic surfactants have good biological activity which is enhanced in case of in-cooperation with AgNPs. Both HPAPH Surfactant and HPAPH/AgNPs nano-hybrid system trigger maximum inhibition zone against all inspected microorganism, compared to surfactant with shorter chain.

Molecular interaction between sodium dodecylbenzene sulfonate and octylphenol polyoxyethylene ether and effect of hydrophilic chain

The micellization behavior of two binary mixtures of an anionic sodium dodecylbenzene sulfonate with a nonionic surfactant octylphenol polyethoxylated ether (including OP-10 or OP-7) was investigated in aqueous solution at 298.15 K using the tensiometry, and the effect of hydrophilic chain of nonionic surfactant was discussed. In the framework of pseudophase separation model and based on the regular solution theory, the related micellization parameters and thermodynamic parameters were estimated by some models including Clint’s model, Rubingh’s model, etc. The two mixtures exist some differences in the micellization behavior. The synergistic effect, the antagonism, nonideal mixing and ideal mixing are observed in the two mixtures. The dependence of the mixed critical micelle concentration, the composition in mixed micelle, the interaction parameter between molecules on the composition in aqueous solution is explained by the electrostatic interaction, the steric effect and the shell structure of mixed micelle, etc. Thermodynamic parameters are adopted to account for the difference in energy and verify the micellization behavior. The two binary mixtures show different contributions of energy to the process of micellization. These findings help with understanding the nature on the interaction between two surfactants and the effect of the length of hydrophilic chain of nonionic surfactant so as to obtain some information in theoretical and practical investigations.

Advanced Eco-Friendly Formulations of Guar Biopolymer-Based Textile Conditioners.

Fabric conditioners are household products used to impart softness and fragrance to textiles. They are colloidal dispersions of cationic double chain surfactants that self-assemble in vesicles. These surfactants are primarily derived from palm oil chemical modification. Reducing the content of these surfactants allows to obtain products with lower environmental impact. Such a reduction, without adverse effects on the characteristics of the softener and its performance, can be achieved by adding hydrophilic biopolymers. Here, we review the role of guar biopolymers modified with cationic or hydroxyl-propyl groups, on the physicochemical properties of the formulation. Electronic and optical microscopy, dynamic light scattering, X-ray scattering and rheology of vesicles dispersion in the absence and presence of guar biopolymers are analyzed. Finally, the deposition of the new formulation on cotton fabrics is examined through scanning electron microscopy and a new protocol based on fluorescent microscopy. With this methodology, it is possible to quantify the deposition of surfactants on cotton fibers. The results show that the approach followed here can facilitate the design of sustainable home-care products.

Implications of surfactant hydrophobic chain architecture on the Surfactant-Skin lipid model interaction

Although surfactants have been widely used in skin care and other related applications, our knowledge about how surfactants interact with stratum corneum (SC) lipids remains limited. This work reports how surfactants interact with a lipid SC model by neutron diffraction and molecular dynamics (MD) simulations, focusing on examining the impact of surfactant molecular architecture. The surfactant-SC mixed membrane was constructed by an equimolar mixture of ceramide/cholesterol/fatty acids and surfactant at 1% molar ratio of total lipids. The arrangements of water and surfactant molecules in the membrane were obtained through neutron scattering length density (NSLD) profiles via contrast variation method, meanwhile, MD simulation clearly demonstrated the mechanism of hydration change in the surfactant-model SC mixed membrane. No drastic difference was detected in the repeating distance of the short periodicity phase (SPP) upon adding surfactants, however, it significantly enhanced the membrane hydration and reduced the amount of phase separated crystalline cholesterol, showing a strong dependence on surfactant chain length, branching and double bond. This work clearly demonstrates how surfactant architecture affects its interaction with the SC membrane, providing useful guidance for either choosing an existing surfactant or designing a new one for surfactant-based transdermal application.

Geometric Frustration and Long-Range Ordering Induced by Surface Pressure Oscillation in a Langmuir-Blodgett Monolayer of Magnetic Soft Spheres.

As a step toward the bottom-up construction of magnonic systems, this paper demonstrates the use of a large-amplitude surface-pressure annealing technique to generate 2-D order in a Langmuir-Blodgett monolayer of magnetic soft spheres comprising a surfactant-encapsulated polyoxometalate. The films show a distorted square lattice interpreted as due to geometric frustration caused by 2-D confinement between soft walls, one being the air interface and the other the aqueous subphase. Hysteresis and relaxation phenomena in the 2-D layers are suggested to be due to folding and time-dependent interpenetration of surfactant chains.

Role of crystallinity on the thermal and viscous behaviour of polyethylene glycol-in-silicone oil (o/o) phase change emulsions

Stable polyethylene glycol-in-silicone oil phase change emulsions were successfully prepared with a selected silicone surfactant. These oil-in-oil (o/o) emulsions have been scarcely examined up, despite the highly remarkable properties of both phases for energy recovery applications and cosmetic/pharmaceutical compositions. The objective of the present work was to study the effect of composition (surfactant and disperse phase concentrations) and the post-processing conditions (further agitation at the processing temperature for 24 h) on the final features of the emulsion. For this purpose, optical morphology, thermo-physical and the rheological behaviour of the emulsions and binary blends of their compounds were measured and analysed. Special attention has been paid to structural changes and crystallinity modifications of the emulsion disperse phase. The observed miscibility of the silicone surfactant and silicone chains with the disperse phase reduces its crystallinity degree and modifies in the crystallization mechanism of the polyethylene glycol, from heterogeneous to homogeneous nucleation. Interestingly, the change in the disperse phase crystallinity remarkably modifies final thermal and rheological properties of the emulsion.

A Nickel/Palladium/Ruthenium-Graphene based nanocatalyst for selective catalytic hydrogenation of vegetable oils

The catalytic hydrogenation of vegetable oils has long been the subject of study. Indeed, the reduction of un-saturations can to improve stability and increase properties suitable for a wide range of applications. Moreover, even with so much effort, the results are still far from the objectives of obtaining cis isomer of monoenes in the presence of a low amount of stearic acid. A new catalyst, obtained from a one-step synthesis, operating in mild conditions with high activity and full selectivity towards the cis configuration of 9-octadecanoic acid was proposed. A Ni/Pd/Ru active phase, with surfactant chains surfaces conjugated, results dispersed on few-layer graphene for increased efficiency exploiting the adsorbent properties of the support.The results demonstrate that the nano-hybrid made up of cheap and available Ni with very small amounts of palladium and ruthenium, allows achieving during hydrogenation of canola oil favorable cis-C18:1/C18:0 ratios, at a low catalyst loading of 1 wt.%. The addition of the Ru active phase allows successfully achieving up to 75.3 wt.% cis C18:1, and 2.46 wt.% of stearic acid, after 60 min. Additionally, it is worth noticing that only 2.6 wt.% of cis C18:1 is constituted of cis positional isomers. The graphene stabilizing nanoparticles ensures catalyst stability over cycles of use.

Assemblies disaggregation and diffusion dictated droplet impact and wetting behaviors on hydrophobic surface

Improving the liquid deposition on plant leaves is crucial during pesticide spraying. However, the hydrophobicity of most plant leaf surfaces makes the droplet splash or run off, finally reducing the efficacy of the foliar-applied pesticide. Though some molecular additives have been employed to regulate the above process, the understanding about the mechanism and the effect of molecular structure is still limited. Herein, cationic surfactants with different double-chain lengths (8–14) are adopted to regulate the droplet impact and wetting on hydrophobic paraffin surface (simulating leaves). With the surfactant chains extending, the capacity for restraining retraction and promoting wetting increases firstly, and then decreases. It can be attributed to that the surfactant with shortest chain cannot form assemblies to inhibit retraction, as the chain length increases, the small-sized micelles reduce but the vesicles become larger and firmer thus the self-assemblies scarcely disaggregate to replenish the monomer at interface during impact. Likewise, short-chain surfactant diffuses faster to interface than long-chain surfactant due to the size effect and hydrophilic/hydrophobic ratio. Our work not only elucidates the mechanism of droplet impact and wetting dynamics by tuning the assemblies aggregation and surfactant diffusion but also promotes the promising application of surfactant in pesticide spraying.

Molecular Packing in a Triphenylene‐Surfactant Complex Monolayer: Unambiguous Determination of Electrostatically Driven Molecular Packing in a Triphenylene–Surfactant Complex Monolayer (Adv. Mater. Interfaces 13/2021)

Self-assembly is a technique of choice for the bottom-up fabrication of molecular devices. In article number 2100187, Snehasis Daschakraborty, Alpana Nayak, and co-workers report intricate details of the self-assembly processes and resultant ordered structures of a technologically useful molecular system comprising of discotic liquid crystal and double chain surfactant.

Influence of Surfactant Additives on Photochemical Synthesized Silver Nanoparticles using UV Pulsed Laser Irradiations in Aqueous Silver Nitrate Solution

The effect of different additives on the AgNPs formation process was explored in this study. AgNPs were synthesized in an aqueous solution of silver nitrate-containing surfactants by photoreduction of silver ions. The concentration dependency of AgNPs formation suggested that stability was induced by the equilibrium of AgNPs adsorbed by surfactants with higher carbon chain molecules such as SDS and AOT. These results open up a new window both for structural control and the development process. It also indicated that different additives had an impact on the morphology of NPs. The hydrocarbon chain influenced the growth process and demonstrated that <10 carbon chain surfactants such as SMS, SOS, did not constitute the CGC and had a minor effect on the mechanism of growth. However, the NPs formation begun at a lower limit indicated as CGC. It was observed only with hydrocarbon chains of > 10 carbon atoms such as AOT, SDS. Fluorescence results confirmed that after laser irradiation, hemi-micelle formation after the development of AgNPs.

An artificial membrane binding protein-polymer surfactant nanocomplex facilitates stem cell adhesion to the cartilage extracellular matrix

One of the major challenges within the emerging field of injectable stem cell therapies for articular cartilage (AC) repair is the retention of sufficient viable cell numbers at the site of injury. Even when delivered via intra-articular injection, the number of stem cells retained at the target is often low and declines rapidly over time. To address this challenge, an artificial plasma membrane binding nanocomplex was rationally designed to provide human mesenchymal stem cells (hMSCs) with increased adhesion to articular cartilage tissue. The nanocomplex comprises the extracellular matrix (ECM) binding peptide of a placenta growth factor-2 (PlGF-2) fused to a supercharged green fluorescent protein (scGFP), which was electrostatically conjugated to anionic polymer surfactant chains to yield [S−]scGFP_PlGF2. The [S−]scGFP_PlGF2 nanocomplex spontaneously inserts into the plasma membrane of hMSCs, is not cytotoxic, and does not inhibit differentiation. The nanocomplex-modified hMSCs showed a significant increase in affinity for immobilised collagen II, a key ECM protein of cartilage, in both static and dynamic cell adhesion assays. Moreover, the cells adhered strongly to bovine ex vivo articular cartilage explants resulting in high cell numbers. These findings suggest that the re-engineering of hMSC membranes with [S−]scGFP_PlGF2 could improve the efficacy of injectable stem cell-based therapies for the treatment of damaged articular cartilage.

Synthesis and Evaluation of a Low Molecular Weight Amphiphilic Polymer for Enhanced Oil Recovery

AbstractIn this work, a novel, low molecular weight amphiphilic polymer (LAP) with high content of surface‐active functional groups was developed, and its effectiveness for emulsion‐based enhanced oil recovery (EOR) in relatively low permeability reservoirs was evaluated. The LAP polymer can potentially be synthesized on an industrial scale through a free radical polymerization reaction between acrylamide (AM), methyl acrylate (MAA), and the unsaturated surfactant monomer 2‐(acylamido)‐dodecane sulfonic acid (C12AMPS). The interfacial tension between 1000 mg L−1 LAP water solution and Bohai crude oil at 50 °C was reduced to a low value of around 0.2 mN m−1. Core flooding tests were also conducted to study the EOR potential and migration properties of LAP in porous media. The resistance and residual resistant factors of 1500 mg L−1 LAP solution were measured to be 51.0 ± 0.1 and 16.5 ± 0.1, respectively, suggesting LAP's great potential to be used for reservoir profile control. In addition, oil recovered from a three‐layer heterogeneous core by LAP solution was found to be comparable to that recovered using alkaline‐surfactant‐polymer (ASP) flooding. It is also worth mentioning that to accommodate different reservoir conditions, the molecular weight of LAP is adjustable by modifying the concentration of chain transfer agent, surfactant monomer, or initiator.

Powerful tailoring effects of counterions of ammonium surfactants on the phase transitions of solvent-free DNA thermotropic liquid crystals

Solvent-free DNA-surfactant thermotropic liquid crystals (TLCs) are new developed soft biomaterials in recent years. The phase transition behaviors of these DNA TLCs could be regulated by the chain lengths of used double chain surfactants. While, the impact of counterions of ammonium surfactants on the phase transitions of DNA TLCs is still not clear. Herein, a series of ammonium surfactants with different counterions were prepared and put into use of fabrication of DNA TLCs. With inorganic counterions, the resulted DNA materials exhibit distinct decrease on the thermodynamic stability of LC states along with the size increase of counterions, while, the use of planar p-toluenesulfonate as counterion leads to remarkable increased LC thermostability for the resulted DNA material, due to the different interaction between counterions and surfactant layers. These observations indicate that the LC property of DNA-surfactant complexes could be conveniently tailored by using surfactants with designed counterions, providing a new strategy for designing advanced solvent-free biomaterials.