十六烷基三甲基溴化铵在二氧化硅表面吸附的研究

十六烷基三甲基溴化铵在亲水二氧化硅表面的吸附呈现出两阶段的特点，在第一阶段对应单分子层吸附，而第二阶段对应双分子层吸附，用椭圆偏振法测出的十六烷基三甲基溴化镓在二氧化硅表面吸附层的厚度表明了这特性。     

Influence of end-group modification on interaction of amphiphilic poly(oxyethylene)-<Emphasis Type="Italic">b</Emphasis>-poly(oxybutylene) block copolymers with ionic surfactants

Amphiphilic poly(oxyethylene)-b-poly(oxybutylene) block copolymers having hydrophilic block end-capped with neutral dimethylamino (DE₇₉B₃₄) and cationic trimethyl ammonium (TE₇₉B₃₄) groups, respectively were investigated for their interactions with ionic surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) using tensiometry, conductometry and dynamic light scattering. The self-assembly of DE₇₉B₃₄ and TE₇₉B₃₄ occur at 0.7 g/dm³ and 0.8 g/dm³, respectively. TE₇₉B₃₄ binds favorably with oppositely charged SDS, causing a substantial change in surface tension compared to other surfactant-polymer systems. In mixed polymer-surfactant systems, the micellization was promoted in the presence of SDS, but it was suppressed with CTAB. Such behavior is expected for cationic block copolymers, since they can engage into ion-pair formation with anionic SDS. For neutral polymers, the behavior is reflective of surfactants’ head group hydrophobicity. The head groups of CTAB are more hydrophobic and their existence in the proximity of hydrophobic segments of polymers induces shape transition to non-spherical morphologies. Gibb’s free energy of adsorption at air – water interface is negative for SDS, CTAB and surfactant-block copolymer systems, indicating that the process is highly spontaneous. The increase in entropy of TE₇₉B₃₄ during micelle formation with temperature is due to disturbance of hydrophobic structure of water molecules, thus hydrophobic parts are removed from bulk solution to the interface and also in the interior of micelle the freedom of hydrophobic part is increased. The dynamic laser light scattering results revealed that due to presence of block copolymers pre-micellar aggregates were favored.     

Mechanistic Studies of Particulate Soil Detergency: II: Hydrophilic Soil Removal

In this work, the removal mechanism of kaolinite and ferric oxide (model hydrophilic particulate soils) from hydrophilic (cotton) and hydrophobic (polyester) fabrics was studied using three surfactant types: sodium dodecyl sulfate (SDS), octylphenol ethoxylate (OP(EO)10), and cetyltrimethylammonium bromide (CTAB). This work investigated the relations between zeta potential, surfactant adsorption, contact angle, solid/liquid spreading pressure, and dispersion stability in washing solutions as compared to detergency performance and antiredeposition as a function of surfactant concentration and pH level. The SDS showed the best detergency for both particulate soils, followed by OP(EO)10, with CTAB being the least effective surfactant. For SDS, the electrostatic repulsion between fabric and soil was found to be the dominant force for hydrophilic particulate soil removal. For the nonionic surfactant OP(EO)10, electrostatics are also important and steric effects aid particulate soil detergency. Electrostatic forces and solid/liquid interfacial tension reduction aids CTAB detergency. These same detergency mechanisms have previously been found for the case of hydrophobic soil removal from fabrics. Dispersion stability did not prove to be a dominant mechanism governing particulate soil detergency. From the SEM photos of soiled fabric, ferric oxide attaches to the fabric surface with no entrapment between fabric yarns; moreover, ferric oxide tends to form larger aggregates on cotton compared to polyester fabric. The adhesion of larger particles is hypothesized to be weaker than the smaller ones. Therefore ferric oxide can be more easily removed from cotton fabric than polyester. The SEM photos for kaolinite show little visual difference in particle agglomeration on polyester compared to cotton. Removal of kaolinite from cotton was found to be higher than from polyester, but there is less difference than for ferric oxide.     

The Location of Phenolic Antioxidants and Radicals at Interfaces Determines Their Activity

To characterize parameters influencing the antioxidant activity at interfaces a novel ESR approach was developed, which facilitates the investigation of the reaction stoichiometry of antioxidants towards stable radicals. To relate the activity of antioxidants towards the location of radicals at interfaces NMR experiments were conducted. Micellar solutions of SDS, Brij and CTAB were used to model interfaces of different chemical nature. The hydrophilic Fremy’s radical was found to be solubilized exclusively in the aqueous phase of SDS micellar solution but partitioned partly into the hydrophilic headgroup area of Brij micelles. In contrast the hydrophobic galvinoxyl was exclusively located in the micellar phase with the increasing depth of intercalation in the order SDS < Brij < CTAB. Gallates revealed a higher stoichiometric factor towards galvinoxyl in CTAB systems, which is accounted to a concentration effect of antioxidant and radical being both solubilized in the palisade layer. In contrast, in SDS solutions hardly any reaction between galvinoxyl and gallates was found. SDS acted as a physical barrier between radical (palisade layer) and antioxidant (stern layer). The influence of the hydrophobic properties of the antioxidant was clearly seen in Brij micelles. Elongation of the alkyl chain in gallate molecule resulted in increasing stoichiometric factors in the presence of galvinoxyl being located in the deeper region of the bulky headgroup area. The reverse trend was found in the presence of Fremy’s radical being located in the hydrated area of the micelles.     

Fabrication of hydrophilic and hydrophobic site on polypropylene nonwoven for removal of bisphenol a from water: explorations on adsorption behaviors,mechanisms and configurational influence

In this study, hydrophilic and hydrophobic site was fabricated onto the surface of polypropylene (PP) nonwoven for removal of bisphenol A (BPA). The adsorption behaviors as well as the adsorption driving forces were systematically analyzed. It is revealed that the amphiphilic PP nonwoven (PP-g-GMA-OA) had strong affinity towards BPA molecules and the predominant driving forces were hydrophobic interaction and hydrogen bonding. The hydrophobic site acted as adsorption site to provide hydrophobic interaction. The hydrophilic site accelerated the diffusion and adsorption process. In addition, the detailed connections between grated layer configuration and adsorption behaviors were observed and systematically elucidated. To ascertain the configurational transformation of grafted layer on PP surface, a microparticle grafting experiment was designed based on stimuli-responsive material measurement and the results indicated that the grafted layer had extended and contracted configuration with the variety of pH. Surface zeta potential measurement revealed that the configurarational transformation was mainly controlled by electrostatic interaction. On the basis of specially designed adsorption isotherm experiment, it is observed that extended configuration could offer more sites and slightly increased the adsorption capacity compared with contracted configuration.     

Understanding the intrinsic water wettability of graphite

We report the effect of airborne hydrocarbon contamination on the water wettability of graphite. Graphite is traditionally known to be hydrophobic with water contact angle (WCA) within the 75–95° range. We found that the WCA of highly ordered pyrolytic graphite (HOPG) was 64.4 ± 2.9° when measured within 10 s after exfoliation in air and increased to ca. 90° after exposure to the ambient air. Ellipsometry measurement showed growth of an adsorptive layer on exfoliated HOPG and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) data indicated that the layer is airborne hydrocarbon. Theoretical calculation confirms that adsorption of only a monolayer amount of hydrocarbon is enough to reproduce the hydrophobic behavior previously observed on HOPG. These results indicated that graphite is intrinsically more hydrophilic than previously believed and that surface adsorbed airborne hydrocarbon is the source of hydrophobicity.     

基于香豆胶的疏水改性阴离子聚电解质溶液性能

将十二烷基（Dod）与十六烷基（Cet）以酯键方式分别引入经羧甲基化改性的香豆胶大分子骨架上,制备了基于香豆胶的疏水改性阴离子聚电解质衍生物（HmCmFG）。通过荧光探针芘的激发光谱、发射光谱以及紫外光谱研究了HmCmFG溶液中的疏水缔合行为,研究发现,此疏水缔合行为受到HmCmFG大分子上烷基链长与取代度以及溶液中小分子电解质NaCl的显著影响,增加烷基链长、提高烷基取代度或增大NaCl浓度均有利于溶液中疏水缔合微区的形成。采用黏度法研究了溶液中HmCmFG大分子与NaCl、表面活性剂十六烷基三甲基溴化铵（CTAB）及十二烷基硫酸钠（SDS）的相互作用。结果表明,Dod取代度小于5.7时,NaCl的加入以增强HmCmFG分子间缔合为主,溶液黏度增加,加入CTAB对于Dod取代度小于5.7时的溶液黏度值的影响高于SDS;Dod取代度为10.2或Cet取代度为6.3时,加入NaCl、CTAB或SDS后使HmCmFG分子内缔合占优势,溶液黏度降低。     

Theory-Guided Design of a Method to Obtain Competitive Balance between U(VI) Adsorption and Swaying Zwitterion-Induced Fouling Resistance on Natural Hemp Fibers

The competitive balance between uranium (VI) (U(VI)) adsorption and fouling resistance is of great significance in guaranteeing the full potential of U(VI) adsorbents in seawater, and it is faced with insufficient research. To fill the gap in this field, a molecular dynamics (MD) simulation was employed to explore the influence and to guide the design of mass-produced natural hemp fibers (HFs). Sulfobetaine (SB)- and carboxybetaine (CB)-type zwitterions containing soft side chains were constructed beside amidoxime (AO) groups on HFs (HFAS and HFAC) to form a hydration layer based on the terminal hydrophilic groups. The soft side chains were swayed by waves to form a hydration-layer area with fouling resistance and to simultaneously expel water molecules surrounding the AO groups. HFAS exhibited greater antifouling properties than that of HFAO and HFAC. The U(VI) adsorption capacity of HFAS was almost 10 times higher than that of HFAO, and the max mass rate of U:V was 4.3 after 35 days of immersion in marine water. This paper offers a theory-guided design of a method to the competitive balance between zwitterion-induced fouling resistance and seawater U(VI) adsorption on natural materials.     

蛋白质在温度响应性PNIPAAm接枝硅胶表面吸附和解吸过程:分子模拟和实验研究(英文)

Poly(N-isopropylacrylamide)(PNIPAAm) grafted onto silica,which may be used for reverse phase chromatography(RPC),was simulated and synthesized for protein separation with temperature-triggered adsorption and desorption.Molecular dynamics simulation at an all-atom level was performed to illustrate the adsorption/desorption behavior of cytochrome c,the model protein,on PNIPAAm-grafted-silica,a temperature responsive adsorbent.At a temperature above the lower critical solution temperature(LCST),the PNIPAAm chains aggregate on the silica surface,forming a hydrophobic surface that is favorable for the hydrophobic adsorption of cytochrome c,which has a high exposure of hydrophobic patches.At temperatures below the LCST,the PNIPAAm chains stretch,forming hydrophilic surface due to hydrogen bonding between PNIPAAm and surrounding water.Desorption of cytochrome c on the PNIPAAm-grafted-silica surface occurs as a result of competition with water,which forms hydrogen bonds with the protein.The conformational transitions of both cytochrome c and PNIPAAm are monitored,providing molecular insight into this temperature-responsive RPC technique.PNIPAAm-grafted-silica beads were synthesized and used for the adsorption and desorption of cytochrome c at approximately 313 K and 290 K,respectively.The experimental results validate the molecular dynamics simulation.In comparison to conventional RPC,using temperature as a driving force for RPC reduces the risk of protein denaturation caused by exposure to chaotropic solvents.Moreover,it simplifies the separation process by avoiding the buffer exchange operations between the steps.     

乳化剂在集料化学成分表面吸附行为的分子模拟与试验论证

采用分子模拟和电导率试验相结合的手段,研究了十二烷基苯磺酸钠（SDBS）和十八烷基三甲基氯化铵（STAC）在酸性集料主要化学成分（SiO₂）和碱性集料主要化学成分（CaCO₃）表面的吸附行为。模拟结果表明：两类乳化剂周围均有两层水化层,STAC的亲水基第一水化层内的水分子个数约为SDBS的两倍,其亲水性强于SDBS;通过界面能分析,对两类乳化剂而言,STAC在集料主要化学成分表面的吸附能力大于SDBS,对于两种集料来说CaCO₃对两类乳化剂的吸附能力较SiO₂强。电导率试验结果表明：不同集料比（乳化剂的质量与集料化学成分的质量比）下,乳化剂在CaCO₃表面的吸附量大于SiO₂,且随集料比的增加,不同集料化学成分对乳化剂的吸附量也增加;CaCO₃和SiO₂对两类乳化剂的吸附曲线近似为S型,且对STAC的吸附曲线离散性小于SDBS;SDBS和STAC在CaCO₃上表面浓度（{\Gamma }_{\mathrm{1}}）最大,另STAC的最大吸附量约为SDBS的3.2倍;模拟参数中的配位数与试验参数中的最大吸附量和乳化剂吸附系数之间的灰色关联度良好,通过配位数可分析乳化剂的亲水性,最大吸附量和吸附系数可用来判断集料对乳化剂的吸附量大小。模拟结果与试验结果一致,表明分子动力学可以准确描述乳化剂在集料主要化学成分表面的吸附行为。     

The investigation of adsorption thermodynamics and mechanism of a cationic surfactant,CTAB, onto powdered active carbon

In this study, the adsorption mechanism of cethyltrimethylammonium bromide (CTAB), a cationic surfactant, onto powdered active carbon (PAC) from aqueous solution was investigated and also some thermodynamic quantities such as isosteric adsorption enthalpy and entropy for this system were determined. In addition, the mechanistic and thermodynamic results of the experiments were supported with the surface zeta potential measurements. It was found that 5 min is sufficient in order to reach adsorption equilibrium. The adsorption of CTAB onto active carbon/water interface mainly takes place through ion exchange, the ion pairing and hydrophobic bonding. The predominant mechanisms in the lower CTAB concentrations are probably ion exchange and ion pairing. The hydrophobic bonding mechanism predominates with the increasing CTAB concentration. It was determined that the signs of isosteric adsorption enthalpy (ΔH_ζ) and isosteric adsorption entropy (ΔS_ζ) for adsorption of CTAB onto PAC are negative and positive, respectively. As temperature increases, the amount of CTAB adsorbed is decreased indicating the exothermic nature of adsorption process. This decreasing verifies the negative sign expected of (ΔH_ads)_ζ. As a result of the adsorption, since the number of the water molecules surrounding the hydrocarbon tails of CTAB molecules decreases and thus the degree of freedom of the water molecules increases, the positive sign of (ΔS_ads)_ζ points out the hydrophobic bonding mechanisms.     

Über das verhalten von sulfonierten naphthalin- und phenol-formaldehyd-kondensationsharzen an grenzflächen

The wetting mechanism of solids by the examined polymers basically differs from the wetting mechanism of surfactants. Aqueous solutions of polymers are not surface-active and show on solids the same contact angle as water. At hydrophobic solids such as graphite or polyethylene, a reversible monomolecular physisorption occurs, which can be described by the LANGMUIR'S equation. In contrast, on polycarbonate plastics, kaolin and porcelain, a largely irreversible adsorption occurs. The irreversibly adsorbed polymer molecules hydrophilize the surfaces of solids, which then retain their hydrophilic properties and can be wettedd even after repeated rinsing. With adsorption on graphite, the adsorbed amount of substance is independent on the ratio liquid volume/adsorbent, whereas with adsorption on kaolin and porcelain the amount of polymers adsorbed in equilibrium increases with an increasing ratio. The adsorption depends upon the external surface area, consequently, the equilibrium adsorption decreases significantly with an increasing grain radius.     

Adsorption and Aggregation Activity of Sodium Dodecyl Sulfate and Rhamnolipid Mixture

Measurements of the surface tension, density and viscosity of sodium dodecyl sulfate (SDS) and rhamnolipid (RL) mixtures were carried out in aqueous solution. From the obtained results, composition of mixed surface layer at the water–air interface, mixed micelles, parameter of intermolecular interactions, activity of SDS and RL in the surface layer and micelles, Gibbs standard free energy of adsorption and micellization as well as Gibbs free energy of SDS and RL mixing in the surface layer and micelles were established. These parameters were discussed in the light of independent adsorption of SDS and RL and the size of their molecules as well as the area in contact with water molecules. A correlation between the number of water molecules in contact with those of SDS and RL and standard free energy of adsorption as well as micellization of these surfactants was observed. A correlation between the apparent and partial molar volumes of RL and SDS in their mixture and size of surfactant molecules as well as the average distance between molecules was also found. The parameter of intermolecular interactions indicates that there is a synergetic effect in the reduction of water surface tension and micelle formation.     

Molecular simulation of CH4 adsorption behavior in slit nanopores: Verification of simulation methods and models

The aim of this study is to select an appropriate method for CH₄ adsorption in organic nanopores for shale-gas development. Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations were performed. Three comparison studies were included: (i) comparison of the adsorption behavior in kerogen nanopores using different schemes for dispersion correction, (ii) comparison of the adsorption behavior in graphite nanopores using MD and GCMC simulations, and (iii) comparison of the adsorption behavior in kerogen and graphite nanopores using MD simulations. The result was reliable when using a particle-mesh Ewald scheme or a cut-off ≥1.5 nm without dispersion correction. The simulation results were essentially identical for the MD and GCMC simulations. The free-gas CH₄ density inside the nanopores started to deviate from the bulk density at ~2 nm for the graphite model and at ~7–10 nm for the kerogen model, whereas the total CH₄ density deviates from the bulk density at ~20 nm.     

Integration or segregation: how do molecules behave at oil/water interfaces?

It has been over 250 years since Benjamin Franklin, fascinated with the wave-stilling effect of oil on water, performed his famous oil-drop experiments; nevertheless, the behavior of water molecules adjacent to hydrophobic surfaces continues to fascinate today. In the 18th century, the calming of the seas seemed the most pertinent application of such knowledge; today, we understand that oil-on-water phenomena underlie a range of important chemical, physical, and biological processes, including micelle and membrane formation, protein folding, chemical separation, oil extraction, nanoparticle formation, and interfacial polymerization. Beyond classical experiments of the oil-water interface, recent interest has focused on deriving a molecular-level picture of this interface or, more generally, of water molecules positioned next to any hydrophobic surface. This Account summarizes more than a decade's work from our laboratories aimed at understanding the nature of the hydrogen bonding occurring between water and a series of organic liquids in contact. Although the common perception is that water molecules and oil molecules positioned at the interface between the immiscible liquids want nothing to do with one another, we have found that weak interactions between these hydrophilic and hydrophobic molecules lead to interesting interfacial behavior, including highly oriented water molecules and layering of the organic medium that extends several molecular layers deep into the bulk organic liquid. For some organic liquids, penetration of oriented water into the organic layer is also apparent, facilitated by molecular interactions established at the molecularly thin region of first contact between the two liquids. The studies involve a combined experimental and computational approach. The primary experimental tool that we have used is vibrational sum frequency spectroscopy (VSFS), a powerful surface-specific vibrational spectroscopic method for measuring the molecular structures of aqueous surfaces. We have compared the results of these spectroscopic studies with our calculated VSF spectra derived from population densities and orientational distributions determined through molecular dynamics (MD) simulations. This combination of experiment and theory provides a powerful opportunity to advance our understanding of molecular processes at aqueous interfaces while also allowing us to test the validity of various molecular models commonly used to describe molecular structure and interactions at such interfaces.     

Effect of dimethyl carbonate on the behavior of water confined in carbon nanotube

The dehydration of water by dimethyl carbonate (DMC) is of great significance for its application in electrochemistry and oil industry. With the rapid development of nanomaterial, one-dimensional (e.g. carbon nanotube (CNT)) and two-dimensional (e.g. lamellar graphene) materials have been widely used for molecular sieving. In this work, the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation. Due to different van der Waals interactions for the components in the mixtures with the solid surface, DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer. Comparing with the pure water molecules confined in CNT, the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement, which may result in different water mobility. Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube. These clear molecular understandings can be useful in material design for membrane separation.     

水化层影响酸酐酶内CO2扩散行为的分子动力学模拟

气相中酶分子表面的水化层对其催化行为具有显著的影响。本文采用全原子分子动力学模拟方法考察了气相体系碳酸酐酶表面的水化层对酶结构以及CO₂在酶分子中扩散行为的影响。首先展现了水分子在酶分子及其活性中心周围的分布,研究了水化层厚度对于酶结构以及CO₂扩散速率的影响;发现最有利于CO₂扩散进入酶分子的水化层厚度为0.7 nm。确认了碳酸酐酶内CO₂的吸附位点,通过对其开合状态统计,显示出碳酸酐酶中CO₂扩散通道中的瓶颈位置。上述结果对设计和优化碳酸酐酶催化气相体系中CO₂的吸附和转化提供了依据和启示。     

碳酸钠对2,3-二甲基-5-(5'-十六烷基)苯磺酸钠在油水界面聚集行为的影响

采用联合原子模型通过分子动力学模拟方法研究了2,3-二甲基-5-(5'-十六烷基)苯磺酸钠(C16-5OXS)在油水界面聚集行为,并考察了弱碱碳酸钠对C16-5OXS聚集行为的影响。模拟结果表明,C16-5OXS可以在油水界面处形成单分子层结构,随着碳酸钠质量浓度增加,界面膜厚度不断降低;碳酸钠质量浓度较低时,并未对C16-5OXS分子的双电层结构产生较大的影响,但当w(Na2CO3)=1.2%时,C16-5OXS分子极性头基的固定层厚度由0.100 nm下降到0.082 nm;同时,C16-5OXS分子的亲水基团占有面积也不断减小,表明C16-5OXS分子在油水界面排列得更加紧密;疏水尾链序参数也随着碳酸钠质量浓度的增加而不断的增加,表明碳酸钠还可以改变疏水尾链在油相中的构象,在微观层次上对弱碱碳酸钠与C16-5OXS分子作用机理进行了描述。     

Interaction of cetyltrimethylammonium bromide with drug in aqueous/ electrolyte solution: A combined conductometric and molecular dynamics method study

Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 K.CFH drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed systems.The decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the cases.The ΔG_m~0 values are found to be negative in present study systems demonstrated the stability of the solution.The values of ΔH_m~0 and ΔS_m~0 reveal the existence of hydrophobic and electrostatic interactions between CFH and CTAB.The thermodynamic properties of transfer for the micellization were also evaluated and discussed in detail.Molecular dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and CTAB.In water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the micelle.This hydrophobic core region is highly conserved and protected.In addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions.     

Study of sodium lignosulfonate prepare low-rank coal-water slurry: Experiments and simulations

The effect of sodium lignosulfonate (SL) as additive on the preparation of low-rank coal-water slurry (LCWS) was studied by experiments and molecular dynamics (MD) simulations. The experimental results show that the appropriate amount of additives is beneficial to reduce the viscosity of LCWS and increase the slurry concentration. Adsorption isotherm studies showed that SL conforms to single-layer adsorption on the coal surface, and △G_ads⁰ was negative, proving that the reaction was spontaneous. Zeta potential measurements showed that SL increased the negative charge on coal. FTIR scanning and XPS wide-range scanning were performed on the coal before and after adsorption, and it was found that the content of oxygen functional groups on coal increased after adsorption. Simulation results show that when a large number of SL molecules exist in the solution, some SL molecules will bind to hydrophobic hydrocarbon groups on coal. The rest of the SL molecules, their hydrophobic alkyl tails, come into contact with each other and aggregate in solution. The agglomeration of SL molecules and the surface of coal with static electricity will also produce electrostatic interaction, which is conducive to the even dispersion of coal particles. The results of mean square displacement (MSD) and self-diffusion coefficient (D) show that the addition of SL reduces the diffusion rate of water molecules. Simulation results correspond to experimental results, indicating that MD simulation is accurate and feasible.