Hydrophilic Head Research Articles

Enhanced excimer fluorescence emission of pyrene derivatives: Applications in artificial light-harvesting systems

Excimer emission usually has a significant Stokes shift, making it an ideal candidate for constructing artificial light-harvesting systems (LHSs). However, the emission of excimers is altered by intermolecular interactions. Precise modulation of the spatial distance and interaction between luminescent units is the key to achieving enhanced emission of excimers. In the current study, electrostatic assembly of polyanionic PSS with cationic bolaamphiphile (PRB) containing pyrene was used to achieve close stacking of pyrene, resulting in significantly enhanced excimer emission. Furthermore, the morphology of the assemblies changed from nanodisks to nanospheres. In particular, the quantum yield of the PRB with PSS increased from 0.5% to 23.1%. In contrast, the amphiphilic molecule containing pyrene with a single hydrophilic head also showed enhanced fluorescence after being co-assembled with PSS. Nevertheless, the fluorescence quantum yield of excimers was much lower than that of the co-assemblies formed with PRB. The assembly formed by PSS and PRB acted as an energy donor. It underwent Förster resonance energy transfer with Nile red, achieving high energy conversion efficiency (ΦET = 49.6%) and antenna effect (9.8) at a donor/acceptor molar ratio of 12.5:1.

Surfactant irritations and allergies

Surfactants are long-chain compounds comprising a hydrophobic tail and a hydrophilic head, lending them the ability to act as a “bridge” between oil and water. Their detergent, foaming and other properties prove useful in a number of settings, including home and workplace sanitation, cosmetics (rinse and no-rinse cleansers) and medicine. When used on skin, surfactants reduce the superficial surface tension of proteins and lipids on the stratum corneum. This helps to eliminate skin debris such as sebum, oils and dirt, but also presents a risk of damage to the skin barrier. The irritation potential of surfactants has long been common knowledge, but with the development and deployment of novel compounds, notably to replace first-generation, mostly sodium-lauryl-sulphate-based products, their potential to cause allergic contact dermatitis has come to light. Knowledge about this allergic potential and the associated dermatitises must also become commonplace so that contact allergies are considered in the presence of surfactant exposure.

Effect of surfactants on the thermoresponse of PNIPAM investigated in the brush geometry

HypothesisAnionic surfactants have been reported to interact with poly(N-isopropyl acrylamide) (PNIPAM), suppressing its thermoresponse. Scattering and NMR studies of the anionic sodium dodecylsulfate (SDS) system propose that the PNIPAM-surfactant interaction is purely hydrophobic. However, prior phenomenological investigations of a range of surfactant identities (anionic, cationic, nonionic) show that only anionic surfactants affect the thermoresponse and conformation of PNIPAM, implying that the hydrophilic head–group also contributes. Crucially, the phenomenological experiments do not measure the affinity of the tested surfactants to the polymer, only their effect on its behaviour. ExperimentsWe study the adsorption of six surfactants within a planar PNIPAM brush system, elucidating the polymer conformation, thermoresponse, and surfactant adsorption kinetics using ellipsometry, neutron reflectometry (NR), optical reflectometry and the quartz crystal microbalance technique. NR is used to measure the distribution of surfactants within the brush. FindingsWe find that only anionic surfactants modify the structure and thermoresponse of PNIPAM, with the greater affinity of anionic surfactants for PNIPAM (relative to cationic and nonionic surfactants) being the primary reason for this behaviour. These results show that the surfactant head–group has a more critical role in mediating PNIPAM-surfactant interaction than previously reported. Taking inspiration from prior molecular dynamics work on the PEO-surfactant system, we propose an interaction mechanism for PNIPAM and SDS that reconciles evidence for hydrophobic interaction with the observed head–group-dependent affinity.

Transition-Linker Containing Detergents for Membrane Protein Studies.

It is a pressing need, but still challenging to explore the structure and function of membrane proteins (MPs). One of the main obstacles is the limited availability of matched detergents for the handling of specific MPs. We describe herein the design of new detergents by incorporation of a transition linker between the hydrophilic head and the hydrophobic tail. This design allows a gradual change of hydrophobicity between the outside and inside of micelles, in contrast to the abrupt switch in conventional detergents. Notably, many of these detergents assembled into micelles in while retaining low critical micelle concentrations. Meanwhile, thermal stabilizing evaluation identified superior detergents for representative MPs, including G protein-coupled receptors and a transporter protein. Among them, further improved the NMR study of MPs. We anticipate these that results will encourage future detergent expansion through new remodeling on the traditional detergent scaffold.

Molecular mechanism study on the effect of nonionic surfactants with different degrees of ethoxylation on the wettability of anthracite

A serious risk to the production safety of coal mines is coal dust. The wettability of coal may be successfully changed by adding surfactants to water. However, the creation of very effective dust suppressants is constrained by the lack of knowledge about the microscopic interaction mechanism between coal dust and surfactants. In this investigation, we explained macroscopic experimental phenomena from a molecular perspective. The lauryl polyoxyethylene ethers (C12 (EO)n, n = 7,15,23) were selected. The macromolecular model of anthracite with 55 different components was constructed. Surface tension experiments and hydrophilic lipophilic balance (HLB) calculations showed that the ability of surface hydrophilicization followed the order of C12 (EO)7<C12 (EO)15<C12 (EO)23. Contact angle experiment, XPS and FTIR experiments proved that after the surfactants were adsorbed on the surface of anthracite, the content of carbon element decreased and the content of oxygen element increased, indicating the enhanced surface hydrophilicity. The simulation results showed that with the degree of ethoxylation increases, the adsorption strength of surfactants becomes stronger, and the hydrophilic head group of surfactant on anthracite surface is more uniformly distributed. The greater the degree of ethoxylation, the more powerfully the modified coal surface can bind to water molecules.

Self-Assembled glycerol monooleate demixes miscible liquids through selective hydrogen bonding to water

Water is miscible with dimethylsulfoxide (DMSO), with which it interacts through hydrogen bonds (H-bonds). Glycerol monooleate (GMO, 53 g/L) demixes water and DMSO, yielding kinetically stable DMSO in water emulsions with up to ≈75 % DMSO (relative to water, v/v), as demonstrated by Fourier Transform Infrared (FTIR) spectromicroscopy, ultra small angle X-ray scattering (USAXS) and light scattering experiments, and optical microscopy. With > 75 % DMSO (relative to water) emulsions reverse and DMSO becomes the continuous phase (as shown by electrical conductivity measurements). The size of emulsified droplets decreases with increasing DMSO ratios (relative to water), as demonstrated by USAXS. Synchrotron X-ray Diffraction (XRD) measurements conducted in the small (SAXS) and wide angle (WAXS) regions show that the DMSO:water ratio affects GMO self-assembly. GMO (53 g/L) self-assembles into cubic crystal mesophases with 40 % DMSO (relative to water) and into disordered lamellar phases with 50 % DMSO. At even higher DMSO percentages, GMO self-assembles into reverse micelles, which contain water and are surrounded by DMSO (as shown by analyzing XRD data with the Steubner and Strey model). Although GMO mainly partitions in the DMSO rich phase, attenuated total reflectance (ATR)-FTIR measurements show that GMO interacts with water through H-bonds. Importantly, it increases the proportion of single H-bond donors (SD, which structure water the most) relative to double donors (DD, which structure water less). H-bonding between the hydrophilic head of GMO and initiates separation between DMSO and water, which would be H-bonded to one another in the absence of GMO. While this study focuses on DMSO, GMO also emulsifies water and tetrahydrofuran (THF), dimethylformamide (DMF) and dioxane. Our findings redefine which solvents can be emulsified with water, and have potential implications for water treatment.

The Effects of the Polarity and Molecular Dynamic Energy of Bamboo Activated Carbon on the Degumming Process of Calophyllum inophyllum Oil

Modified bamboo activated carbon (BAC) was added to non-edible Calophyllum inophyllum oil in a degumming process. The effects of its polarity and molecular dynamic energy on the degumming process were evaluated using characterizations and hyperChem software simulation. It was found that BAC acquired positive surface charge, polar characteristic, and mesoporous structures. The addition of BAC in the degumming process resulted in sufficient molecular dynamic energy (108.83 kcal/mol at 353K) as simulated by hyperChem, playing a role in facilitating successful dephospholipidation. Negatively charged oxygen around the hydrophilic phosphate head group of phospholipids was induced by BAC. The force exerted helped to loosen bonds around the polar head group. Interaction between BAC and polar water molecules also occurred, facilitating more hydrolysis reaction. These actions led to a higher possibility of phosphate head group removal off the phospholipid molecules. Consequently, there were large decreases in phosphorus, magnesium, and calcium concentrations along with small improvements in viscosity and calorific value in the degummed oil.

Self-assembling branched amphiphilic peptides for targeted delivery of small molecule anticancer drugs

Water insolubility poses a significant challenge in the clinical applications of many small molecule drugs. To improve the drug delivery efficiency, two branched amphiphilic peptides (BAPs) were designed in a computer-aided manner, for drug-loading through peptide self-assembling. The structures of the two BAPs, bis(LVFFA)-K-RGD (PepV-1) and bis(FHF)-K-RGD (PepV-2), were inspired by phospholipids, containing the RGD sequence as the hydrophilic head and two hydrophobic sequences as the hydrophobic tails. PepV-1 could self-assemble into nano-fibrils with a hydrophobic core and the RGD moiety on the surface. Its drug-loading efficiency (DE%) of three small molecule anticancer drugs (doxorubicin, camptothecin and curcumin) ranged from 9.90% to 11.74%, and entrapment efficiency (EE%) ranged from 37.30% to 43.00%. Pep-V2 could self-assemble into bilayer delimited nano-vesicles. The DE% of PepV-2 for these drugs ranged from 15.87% to 18.55%, and the EE% ranged from 60.45% to 73.23%. Both BAP carriers could prolong the release of the small molecule drugs, and the PepV-2 vesicles also showed pH-triggered increase of drug release due to the histidine residues. Bothe BAP carriers could increase the cytotoxicity against cancer cells, which might be due to the targeting on the cancer overexpressed integrins. The designed BAP carriers represent promising functional drug carriers for targeted drug delivery, and will be useful for improving the clinical use of small molecule drugs, especially for those with poor water solubility.

Relevance of lipoproteins, membranes, and extracellular vesicles in understanding C-reactive protein biochemical structure and biological activities.

Early purification protocols for C-reactive protein (CRP) often involved co-isolation of lipoproteins, primarily very low-density lipoproteins (VLDLs). The interaction with lipid particles was initially attributed to CRP’s calcium-dependent binding affinity for its primary ligand—phosphocholine—the predominant hydrophilic head group expressed on phospholipids of most lipoprotein particles. Later, CRP was shown to additionally express binding affinity for apolipoprotein B (apo B), a predominant apolipoprotein of both VLDL and LDL particles. Apo B interaction with CRP was shown to be mediated by a cationic peptide sequence in apo B. Optimal apo B binding required CRP to be surface immobilized or aggregated, treatments now known to structurally change CRP from its serum soluble pentamer isoform (i.e., pCRP) into its poorly soluble, modified, monomeric isoform (i.e., mCRP). Other cationic ligands have been described for CRP which affect complement activation, histone bioactivities, and interactions with membranes. mCRP, but not pCRP, binds cholesterol and activates signaling pathways that activate pro-inflammatory bioactivities long associated with CRP as a biomarker. Hence, a key step to express CRP’s biofunctions is its conversion into its mCRP isoform. Conversion occurs when (1) pCRP binds to a membrane surface expressed ligand (often phosphocholine); (2) biochemical forces associated with binding cause relaxation/partial dissociation of secondary and tertiary structures into a swollen membrane bound intermediate (described as mCRPm or pCRP*); (3) further structural relaxation which leads to total, irreversible dissociation of the pentamer into mCRP and expression of a cholesterol/multi-ligand binding sequence that extends into the subunit core; (4) reduction of the CRP subunit intrachain disulfide bond which enhances CRP’s binding accessibility for various ligands and activates acute phase proinflammatory responses. Taken together, the biofunctions of CRP involve both lipid and protein interactions and a conformational rearrangement of higher order structure that affects its role as a mediator of inflammatory responses.

Simulation of surfactant adsorption at liquid-liquid interface: What we may expect from soft-core models?

The present work attempts to systematically explore the surfactant sorption at liquid-liquid interfaces with coarse-grained models targeting thermodynamic properties of reference liquid solutions. We employ dissipative particle dynamics with soft-core forcefield tested against experimental data on micellization of surfactants in water, and the previous results are reproduced in this work. We consider three different nonionic surfactants: hexaethylene glycol monododecyl ether (C12E6), 2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) known as Triton X-100 (TX-100), and two alkyl glucoside surfactants (CnG1) with n-alkane tail fragments and a saccharide hydrophilic head at decane-water and toluene-water interfaces. For TX-100, we composed a model based on the literature forcefield and found good agreement with the experimental critical micelle concentrations (CMCs). The head-head interactions are of different origins for different surfactant groups: entropic repulsion between ethylene oxide chains of C12E6 and TX-100, and more chemically specific and complex interactions between the maltose heads of alkyl glucosides. We interpret our results with the Redlich-Peterson equation of monolayer adsorption in order to relate the adsorption to the bulk concentration of the surfactant and the interfacial tension. The densities of the adsorbed monolayer at CMC mostly agree with the experimental data, and a reasonable agreement was obtained for the interfacial tension at CMC. At the same time, we found significant discrepancies between the simulated and experimental adsorption isotherms. We explain them by the oversimplified forcefield: when the parameters are fitted to the free energies of bulk solutions, they may not correctly reproduce the interfacial free energies.

Membranes and Transport Mechanisms

Cellular life depends on the movement of membrane ions. For cells to continue functioning as they go through their life cycle, there must be a tremendous amount of exchange. Cell membranes are active structures rather than merely passive barriers separating cells from their surroundings. Cell membranes are known to be selectively permeable, allowing some chemicals to pass through while preventing others from doing so. Therefore, all cellular exchange activities can have active participation from cell membranes. Through the membrane interface, elements needed for cellular existence, communication among cells, and interaction between cells and their environment are taken in. Additionally, cells have the ability to direct and influence input and export processes, as well as moderate the subsequent signal response. Effective drug transportation across cellular membranes is essential for all treatment procedures. The majority of medications used in cancer therapy require carrier proteins for their transmembrane transport, even though hydrophobic small molecules can enter the cell membrane through straightforward diffusion. As a result, many scientists concentrate on creating novel strategies to improve drug delivery and uptake into desired cells. A live cell's plasma membrane serves as its outer wall. Although it acts as a barrier, it also permits transport between the cell and its surroundings.&#x0D; While the hydrophilic head groups are in contact with the surrounding water, the bilayer's hydrophobic interior, which is made up of fatty acid chains, renders the membrane impermeable to water-soluble compounds. To reduce the accessibility of hydrophobic fatty acid chains, phospholipids can spontaneously form stable bilayers in an aqueous environment due to their amphipathic nature. As lipids and proteins positioned in the plasma membrane can rotate or diffuse laterally and are distributed asymmetrically in the two leaflets, membranes are extremely dynamic structures. In addition to glycolipids, the outer leaflet of the plasma membrane mostly consists of the phospholipids phosphatidylcholine and sphingomyelin. Phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol are the three main substances that make up the inner leaflet.&#x0D; Additionally, both leaflets contain cholesterol, which affects the fluidity of the membrane. Lipid rafts are particular domains abundant in sphingolipids and cholesterol. The plasma membrane's basic role as a selectively permeable wall dividing the inside from the outside of the cell is determined by the structure of the phospholipid bilayer. Membrane proteins are essential for guaranteeing the selective translocation of molecules across the membrane as well as the regulation of cellular connections. They can function as energy converters, ion channels, pumps, receptors, or enzymes. The maintenance of the osmotic pressure and cellular pH, as well as the regulation of drug uptake mechanisms, account for the regulation of fundamental cellular activities.

Construction of ultrasound-responsive urokinase precise controlled-release nanoliposome applied for thrombolysis.

Urokinase is widely used in the dissolution of an acute pulmonary embolism due to its high biocatalytic effect. However, how to precisely regulate its dose, avoid the side effects of hemolysis or ineffective thrombolysis caused by too high or too low a dose, and seize the golden time of acute pulmonary embolism are the key factors for its clinical promotion. Therefore, based on the precise design of a molecular structure, an ultrasonic-responsive nanoliposome capsule was prepared in this paper. Singlet oxygen is continuously generated under the interaction of the ultrasonic cavitation effect and the sonosensitizer protoporphyrin, and the generated singlet oxygen will break the thiol acetone bond between the hydrophilic head and the hydrophobic tail of the liposome, and the lipid The body structure disintegrates rapidly, and the urokinase encapsulated inside is rapidly released, down-regulating the expression of fibrinogen in the body, and exerting a thrombolytic function. The in vitro and in vivo results show that the smart urokinase nanoliposomes prepared by us have sensitive and responsive cytocompatibility to ultrasound and good in vivo thrombolytic properties for acute pulmonary embolism, which provides a new strategy for clinical acute pulmonary embolism thrombolysis.

The Effect of pH on the Structure and Lateral Organization of Cardiolipin in Langmuir Monolayers.

Cardiolipin (CL) is a unique phospholipid featuring a dimeric structure. With its four alkyl chains, it has a large hydrophobic region and the charged hydrophilic head group is relatively small. Biological membranes exhibit CL exclusively in the inner bacterial and mitochondrial membranes. Alteration of CL packing can lead to structural changes and membrane instabilities. One environmental influence is the change in pH. Since the acidic properties of the phosphate head groups remain still controversial in literature, this work focusses on the influence of pH on the ionization degree of CL. For the analyses, surface pressure (π) - molecular area (A) isotherm experiments were combined with total reflection X-ray fluorescence (TRXF) and grazing incidence X-ray diffraction (GIXD). Continuous ionization with a high CL packing density was observed in the monolayer over a wide pH range. No individual pKa values can be assigned to the two phosphate groups, but mutual influence is observed.

Synthesis of branched surfactant via ethoxylation of oleic acid derivative and its surface properties

A class of bio-based nonionic surfactants with double hydrophilic head groups (DMOE n ) was obtained from the waste cooking oil. • A new strategy for the preparation of branched surfactants from renewable oleic acid in waste cooking oil was proposed, and a class of bio-based nonionic surfactants with double hydrophilic head groups (DMOE n ) was obtained. • The ethoxylation reaction process of DMO and its reaction kinetic were both systematically optimized and studied. • The surface activities, aggregation and adsorption behaviors of DMOE n were investigated, and it was discovered that DMOE n had the characteristics of typical branched surfactant with good wetting performance, low foaming and strong defoaming ability. A new series of bio-based branched nonionic surfactants (ethoxylated dihydroxy stearic acid methyl ester, DMOE n ) was synthesized and characterized. DMOE n was based on a hydroxyoctadecanoic acid methyl ester, which was obtained from renewable oleic acid in waste cooking oil. These new polyoxyethylene surfactants contained double hydrophilic and hydrophobic chains, which shows the surface properties of the branched surfactant. The synthesis rules and reaction kinetics were studied in detail. The physicochemical properties and surface properties of the DMOE n with different degrees of ethoxylation at various concentrations were investigated. Furthermore, the surface tension results indicate that DMOE n reduced the surface tension reduction and increased the diffusion rate in an aqueous solution. The dynamic contact angle, wettability, foaming properties, and emulsifying capacity tests showed that DMOE n exhibited good wetting performance, low foaming, fast defoaming, and excellent emulsifying ability, which shows that the surfactant has potential application in industrial cleaning.

Elucidating the binding mechanism of LPA species and analogs in an LPA4 receptor homology model

Lysophosphatidic acid receptor 4 (LPA4) has emerged as a potential therapeutic target for the treatment of a variety of diseases, including cancer and obesity-induced diabetes, but its structure remains to be revealed. In the present work, a homology model of LPA4 was built for studying the binding mechanism of LPA species and analogs. Then five selected LPA species and analogs with structural variations in their phosphate groups, substitutions on the glycerol backbone, and fatty acyl chains were docked into the LPA4 model, followed by molecular dynamics simulations and energy analyses. The computational results revealed that the aliphatic residues located at the vertical cleft of LPA4 may form a hydrophobic environment for the fatty acyl moiety of LPA species and their analogs. Meanwhile, the positively charged residues in the central cavity of LPA4 may form ionic interactions with the negatively charged hydrophilic head group of LPA species and their analogs. In addition, it was noted that a different binding mode of the hydrophilic head group in each species with the central cavity of the LPA4 might lead to a special rearrangement of the fatty acyl moiety. Taken together, these results may facilitate understanding of the activation mechanism of LPA4 and help design selective ligands to modulate its function for therapeutic purposes.

Cationic Surfactants as Disinfectants against SARS-CoV-2.

The virucidal activity of a series of cationic surfactants differing in the length and number of hydrophobic tails (at the same hydrophilic head) and the structure of the hydrophilic head (at the same length of the hydrophobic n-alkyl tail) was compared. It was shown that an increase in the length and number of hydrophobic tails, as well as the presence of a benzene ring in the surfactant molecule, enhance the virucidal activity of the surfactant against SARS-CoV-2. This may be due to the more pronounced ability of such surfactants to penetrate and destroy the phospholipid membrane of the virus. Among the cationic surfactants studied, didodecyldimethylammonium bromide was shown to be the most efficient as a disinfectant, its 50% effective concentration (EC50) being equal to 0.016 mM. Two surfactants (didodecyldimethylammonium bromide and benzalkonium chloride) can deactivate SARS-CoV-2 in as little as 5 s.

Branched polyoxyethylene surfactants with different hydrophilic head groups from fatty acid derivatives

New branched polyoxyethylene surfactants with different hydrophilic head groups have been synthesized from fatty acid derivatives as renewable resources. Through a systematic study of the surfactant properties of the obtained substances, ethoxylated monohydroxy stearic acid methyl ester (12-HMEEn) with a single hydrophilic head group, similar to commercial Guerbet alcohol polyoxyethylene ether, has been identified as the most promising candidate. It has excellent surfactant properties including good wettability, low foaming, and strong defoaming ability, indicating that it could be useful in industrial cleaning.

Dual-Stage Blue-Light-Guided Membrane and DNA-Targeted Photodynamic Inactivation Using Octyl Gallate for Ultraefficient Eradication of Planktonic Bacteria and Sessile Biofilms.

This study aimed to investigate the synergistic bactericidal activity and mechanism of dual-stage light-guided membrane and DNA-targeted photodynamic inactivation (PDI) by the combination of blue light (BL, 420 nm) and the food additive octyl gallate (OG) against Vibrio parahaemolyticus in planktonic and biofilm growth modes. While OG serves as an outstanding exogenous photosensitizer, the planktonic cells were not visibly detectable after the OG-mediated PDI treatment with 0.2 mM OG within 15 min (191.7 J/cm2), and its biofilm was nearly eradicated within 60 min (383.4 J/cm2). Gram-positive Staphylococcus aureus was more susceptible to the PDI than Gram-negative V. parahaemolyticus. The cellular wall and proteins, as well as DNA, were the vulnerable targets for PDI. The membrane integrity could be initially disrupted by OG bearing a hydrophilic head and a hydrophobic tail via transmembrane insertion. The enhancement of OG uptake due to the first-stage light-assisted photochemical internalization (PCI) promoted the accumulation of OG in cells. It further boosted the second-stage light irradiation of the photosensitizer-inducing massive cell death. Upon the second-stage BL irradiation, reactive oxygen species (ROS) generated through the OG-mediated PDI in situ could extensively deconstruct membranes, proteins, and DNA, as well as biofilms, while OG could be activated by BL to carry out photochemical reactions involving the formation of OG-bacterial membrane protein (BMP) covalent conjugates and the interactions with DNA. This dual-stage light-guided subcellular dual-targeted PDI strategy exhibits encouraging effects on the eradication of planktonic bacteria and sessile biofilms, which provides a new insight into the development of an ultraeffective antimicrobial and biofilm removing/reducing technique to improve microbiological safety in the food industry.

Ugi Reaction Mediated Detergent Assembly for Membrane Protein Studies.

Despite the continuous efforts, the current repertoire of detergents is still far from sufficient for the biophysics studies of membrane proteins (MPs). Toward the rapid expansion of detergent diversity, we herein report a new strategy based on Ugi reaction mediated modular assembly. Structural varieties, including hydrophobic tails and hydrophilic heads, could be conveniently introduced from the multiple reaction components. New detergents then were comprehensively evaluated in the physical properties and preliminarily screened by the thermal stabilization for a transporter MsbA and a spectrum of G protein-coupled receptors (GPCRs). For the glucagon-like peptide-1 receptor (GLP-1R), a class B GPCR, detergent M-23-M finally stood out in a second evaluation for the maintenance of homogeneity and was further illustrated its application in the improvement of NMR study. Besides the promising utility in the MP study, the current results exhibit intriguing structural-physical relationship that would allow the guidance in the tuning of detergent properties in the future.

Anionic surfactant based on oil-solid interfacial interaction control for efficient residual oil development

A large amount of oil film remains on the rock surface after conventional oil displacement methods. Developing novel surfactant to achieve efficient oil film peeling, and unveiling the oil-solid interaction mechanism behind is of great significance. Herein, a novel anionic surfactant 1,2-decanediol dihydroxypropyl sulfonates (D-diHS), which was composed of one hydrophobic tail and two branched hydrophilic heads containing hydroxyl groups and sulfonate groups was synthesized via a feasible two-step reaction. The experimental results showed that D-diHS could alter the wettability of rock surface from oleophilic to strong hydrophilic, with the water contact angle reducing substantially from 100.8° to 17.8°. Compared with traditional surfactants, D-diHS exhibited superior oil film peeling performance with excellent salinity tolerance (oil film reduction rate >74.3 % at 6 wt% salinity). Based on the nano-mechanical experimental results, the reduced adhesion caused by improved hydrophilicity and the produced electrostatic repulsion between the oil film and rock surface played crucial roles in the oil film peeling. The novel anionic surfactant D-diHS proposed in this work was designed from the perspective of oil-solid interfacial interaction control, exhibiting great application potential in efficient residual oil development.