Antimicrobial resistance (AMR) is fast becoming a global healthcare burden, aggravated by the overuse and misuse of antibiotics. To reduce AMR-associated mobility, mortality and cost, we must actively seek alternative treatments, not primarily relying on antibiotics. Gram-negative bacteria, particularly E. coli and P. aeruginosa, are responsible for many AMR casualties worldwide. Rationally designed antimicrobial peptides (AMPs) are promising agents which destroy bacteria by direct and fast membrane disruption, impairing the ability of microbial pathogens to develop AMR. Here, we have explored how AMP's actions change based on selective substitutions of Lysine with Serine in the amino acid sequence of a designed AMP G(IIKK)3I-NH2. Through antimicrobial assays, neutron reflection and molecular dynamics (MD) simulations, we examined how alternating charges and amphiphilicity can impose different structural disruptions to the inner and outer membranes of Gram-negative bacteria, linking intramembrane aggregations to the improved antimicrobial actions of Serine-rich AMPs. The combined experiments and simulations have demonstrated the great potential of Serine-containing AMPs for further development into medical treatment against AMR infections.

The interfacial stability of therapeutic monoclonal antibodies (mAbs) remains a critical challenge in pharmaceutical development, particularly in the context of biocompatible silicone oil-coated delivery devices. Here, we present a molecular-level investigation of antibody conformational dynamics at model polydimethylsiloxane (PDMS) interfaces under varying pH conditions. Using a multi-technique approach combining neutron reflection (NR), spectroscopic ellipsometry (SE), and quartz crystal microbalance with dissipation (QCM-D), the pH-dependent structural adaptations of two engineered antibodies, COE-3 and COE-7, and their constituent Fab and Fc fragments were revealed. Both COE-3 and COE-7 underwent distinct conformational transitions between pH 5.5 and 8.0, with a remarkable shift from monolayer to bilayer architectures. At pH 5.5, both antibodies formed compressed monolayers, indicating substantial molecular deformation. As pH approached the isoelectric point (pH 8.0), a unique bilayer architecture emerged, with a densely packed inner layer supporting a more diffuse and non-deformed outer layer. Notably, this pH-induced structural reorganization was primarily driven by the Fc region, while the Fab fragments maintained consistent monolayer conformations regardless of pH conditions. Our work has established a quantitative framework for illustrating antibody-surface interactions and the contribution of individual fragments in the adsorption process. This mechanistic understanding opens new avenues for enhancing the stability of antibody-based pharmaceuticals on silicone oil-coated delivery devices.

Hypothesis: Nanoscale characterisation of the self-associated species formed by amphiphilic pharmaceuticals in aqueous solution carries relevance across their entire journey from development through to manufacture - relevant, therefore, not only as regards formulation of the drug products as medicines, but also potentially relevant to their bioavailability, activity, and clinical side effects. Such knowledge and understanding, however, can only be fully secured by applying a range of experimental and theoretical methodologies. Experiments: Herein, we apply a synergistic combination of solubility, surface tension, SANS, NMR and UV spectroscopic studies, together with MD simulation and QM calculations, to investigate the meso-structures of propranolol hydrochloride aggregates in bulk aqueous solutions, at concentrations spanning 2.5 mM to > 200 mM. In addition, we explore the effects of adding NaCl to mimic the ionic strength of physiological fluids, and the differences between racemate and single enantiomer. Findings: There is a continuum of particle sizes shown to exist across the entire concentration range, with molecules joining and leaving on the nanosecond timescale, and with the distributions of aggregate sizes varying with drug and salt concentration. Given that propranolol is a highly prescribed (WHO essential) medicine, disfavouring aggregators from consideration in high-throughput screening for potential new drug candidates- as many have advocated- should thus be done cautiously.

Quaternary ammonium compounds (QACs) combined with nonionic surfactants have been among the most effective disinfectants for over half a century, leveraging QACs' broad-spectrum antimicrobial activity that targets microbial membranes. However, the specific interactions between QACs and microbial membranes, as well as the role of nonionic surfactants in disinfection, remain unclear. This study investigates these mechanisms using two representative surfactants: the cationic didecyldimethyl ammonium chloride (DDAC) and the nonionic hexaethylene glycol monododecyl ether (C12E6). The antimicrobial activity of these agents, individually and sequentially, was assessed against Gram-negative bacteria through a series of in vitro assays, including outer membrane (OM) permeability, inner membrane (IM) depolarization, and live/dead bacterial imaging. Further insights into membrane interactions were obtained using model lipid bilayers in conjunction with antimicrobial efficacy matrices, FICI (fractional inhibition concentration index), fluorescent liposome leakage, small-angle neutron scattering (SANS), and neutron reflectivity (NR). Results indicate that C12E6 binds to the rough A lipopolysaccharide (RaLPS) head region in the OM, reassembling it into heterogeneous aggregates but with limited penetration to cause IM disruption. Conversely, DDAC induced structural disruptions in both OM and IM, resulting in low inhibitory concentrations and rapid bacterial killing. In mixtures, the C12E6 : DDAC ratio significantly influences antimicrobial efficacy, with higher C12E6 levels inhibiting DDAC's effective membrane interactions.

The sol-gel transition of CO2-responsive polyelectrolytes is driven by electrostatic interactions between anionic groups and protonated cationic moieties, yet the critical roles of ionic stoichiometry and spatial architecture in mediating gelation behavior remain poorly understood. To address this knowledge gap, two distinct copolymer series with varying configurations and anion/CO2-responsive monomer ratios were synthesized: P(AA-co-DPM) random copolymers via free radical copolymerization of acrylamide, acrylic acid, and dimethylaminopropyl methacrylamide (DMAPMAm), while PAA-g-PDPM graft copolymers through the covalent attachment of poly(DMAPMAm) side chains to poly(AM-co-AA) backbones. CO2-induced protonation led to contrasting phase behaviors contingent on ionic balance. For P(AA-co-DPM) aqueous solution, viscosity decreased when n(DMAPMAm) <= 0.83n(NaAA), increased when n DMAPMAm >= 1.13 n(NaAA), and resulted in precipitation when n(DMAPMAm) = 0.83n(NaAA). Conversely, the PAA-g-PDPM aqueous solution exhibited continuous viscosity enhancement up to n DMAPMAm <= 0.65n(NaAA), followed by dehydration at higher cationic ratios. Notably, the graft architecture demonstrated superior gelation under CO2 exposure, forming robust hydrogels with frequency-independent modulus (0.01-0.1 rads(-1)) and minimal energy dissipation (tan delta < 0.1). In contrast, random copolymers yielded fragile networks displaying frequency-dependent moduli and elevated tan delta (>0.1). Rheology-small angle neutron scattering analysis revealed that graft copolymers underwent CO2-induced chain collapse from swollen to compact conformations, creating physical cross-links, whereas random chains maintained Gaussian statistics regardless of protonation state. These findings highlight that extended cationic side chains in graft architectures enhance intermolecular entanglement and directional electrostatic interactions, offering a strategic approach for designing CO2-responsive hydrogels with tailored mechanical properties through molecular architecture engineering.

Antimicrobial peptides (AMP) offer an attractive alternative to antibiotics in the global fight against antibiotic resistance. AMPs can impose fast structural disruptions to microbial membranes and kill pathogens by causing the leakage of their internal contents, making it less likely for pathogens to develop resistance. However, current AMPs still suffer from various drawbacks including weak efficacy, unacceptable toxicity, and side effects. This work seeks to design a group of amphiphilic AMPs based on the α2 sequence of a Dengue viral capsid protein to address the challenge of ineffective membrane disruptions of AMPs. The design was also inspired by well-studied G(IIKK)3I-NH2 (G3) for broad-spectrum antimicrobial actions. All designed Dengue viral-inspired peptides displayed lower minimum inhibition concentrations and faster time-dependent killing than G3, with the fastest DVP-3 (RIFRAIRRIARFIR) achieving complete killing within 10 min. Fluorescence assays of AMP binding to bacterial membranes revealed varying degrees of membrane permeability change, depolarization, and leakage. Model inner membrane (IM) and outer membrane (OM) of Gram-negative bacteria facilitated leakage assay and neutron reflection, linking membrane binding and disruptions with antimicrobial behaviors. The findings reveal that DVP-3 could cause more effective disruptions to the bacterial OM than to the IM, consistent with its potent antimicrobial efficacy and rapid dynamic killing. This work offers new insights into how the newly designed AMPs destabilize bacterial membranes to improve antimicrobial performance and the combined approach allows effective in vitro AMP evaluation to overcome bacterial resistance.

Thermoviscosifying polymers (TVPs), which thicken aqueous solutions upon heating, deviate from the conventional thermothinning behavior and hold promise as effective rheology modifiers under harsh conditions. However, their thickening efficiency at low concentrations remains limited by relatively low molecular weights, and the quantitative relationship between thermoviscosifying capacity and thermoassociative contributions has yet to be fully established. In this work, model TVPs were synthesized by grafting amino-terminated poly(N-isopropylacrylamide) (PNIPAM) onto high-molecular-weight partially hydrolyzed polyacrylamide, with systematic variations in backbone molecular weight (M w) and graft ratio (G r). A dual-model strategy was adopted to quantify the non-Arrhenius viscosity increase in the thermoviscosifying regime: the Cross model captured logarithmical viscosity growth, while the Gompertz function described sigmoidal viscosity amplification. By integrating molecular parameters into the Gompertz framework, scaling relationships were established between the thickening amplitude (eta max-eta ass) and M w, G r, and polymer concentration (C p), yielding eta max-eta ass similar to M w 1.75, similar to G r 1.04 and similar to C p 2.01, as exemplified by eta ( T , M w ) = eta a s s + K M w 1.75 e - e - k ( T - T c ) . The net thickening power, eta-eta ass, representing the thermoassociative contribution beyond the nonassociative baseline, scales with PNIPAM content (C PNIPAM) as eta-eta ass similar to C PNIPAM n . Analysis using the time-temperature superposition shift factor revealed distinct scaling exponents (n = 2.78 for C p vs 1.10 for G r), highlighting the stronger influence of backbone concentration over grafting density in promoting thermoassociation. These findings provide a quantitative paradigm for assessing thickening performance and establish molecular design principles for TVPs.

Emulsion catalysis, a subset of ’on-water’ catalysis, is influenced by surfactants that act as emulsion stabilizers. The hydrophobicity of these surfactants, closely tied to the molecular structure of their chains and their headgroup ionization, plays a crucial role in controlling emulsion reactions and subsequent processes of surfactant recovery and product purification. However, the influence of the specific chain structure of surfactants and its cooperation with the headgroup in different solution environments on the emulsion reaction and demulsification processes remains uncertain. In this study, the stability of emulsions stabilized by amino acid surfactants featuring various hydrophobic chains, specifically side chains, was studied across a range of pH conditions. Amino acid surfactants with long chain are pivotal in enhancing the stability of emulsions. The combined effect of hydrogen bonding and electrostatic interactions between the amino acid headgroups boosts the stability when the pH of the solution aligns closely with the pKa2 of the surfactants. Under these conditions, a relatively stable oil–water interface significantly increases the yield of the Knoevenagel reaction to 94 %. As the pH of the system increases, the surfactants become more hydrophilic, enabling the phase separation of the emulsion, which facilitates the collection of the product and the recycling of the surfactants. This study provides important insights on regulating the structure and function of the oil–water interface based on surfactants and proposes a potentially effective approach for environmental-friendly and convenient chemical synthesis.

HYPOTHESIS:Cationic surfactants have a wide range of applications, often associated with their affinity for a range of solid surfaces and their anti-microbial properties. Manipulating their adsorption and self-assembly properties is key to most applications, and this is commonly achieved through surfactant mixtures or manipulating their headgroup or alkyl chain structure. Achieving this through adjustments to their headgroup structure is less common in cationic surfactants than in anionic surfactants. Ethoxylation provides the ability to adjust the hydrophilic / hydrophobic balance, as extensively demonstrated in a range of anionic surfactants. EXPERIMENTS:This same approach has been applied here to a range of ethoxylated cationic surfactants in the form of the quaternary ammonium salts, and their tertiary nonionic equivalents before quaternisation. Their adsorption and self-assembly properties are investigated using predominantly the neutron scattering techniques of neutron reflectivity, NR, and small angle neutron scattering, SANS. FINDINGS:The trends in the adsorption at the air-water interface and the self-assembly in aqueous solution demonstrate how the hydrophilic / hydrophobic balance can be adjusted by varying the degree of ethoxylation and the alkyl chain length, and illustrate the degree of interdependence of the different structural changes. The variation in the adsorption and the micelle structure shows how the surfactant conformation / packing changes as the degree of ethoxylation and alkyl chain length increases and how the introduction of charge induces further changes.

Sphingosine, an amphiphilic molecule, plays a pivotal role as the core structure of sphingolipids, essential constituents of cell membranes. Its unique capability to enhance the permeability of lipid membranes profoundly influences crucial life processes. The molecular structure of sphingosine dictates its mode of entry into lipid bilayers and governs its interactions with lipids, thereby determining membrane permeability. However, the incomplete elucidation of the relationship between the molecular structure of sphingosine and the permeability of lipid membranes persists due to challenges associated with synthesizing sphingosine molecules. A series of sphingosine-derived molecules, featuring diverse hydrophobic chain lengths and distinct headgroup structure, were meticulously designed and successfully synthesized. These molecules were employed to investigate the permeability of large unilamellar vesicles, functioning as model lipid bilayers. With a decrease in the hydrophobic chain length of sphingosine from C15 to C11, the transient leakage ratio of vesicle contents escalated from ∼ 13 % to ∼ 28 %. Although the presence of double bond did not exert a pronounced influence on transient leakage, it significantly affected the continuous leakage ratio. Conversely, modifying the chirality of the C-3 hydroxyl group gives the opposite result. Notably, methylation at the C-3 hydroxyl significantly elevates transient leakage while suppressing the continuous leakage ratio. Additionally, sphingosines that significantly affect vesicle permeability tend to have a more pronounced impact on cell viability. Throughout this leakage process, the charge state of sphingosine-derived molecule aggregates in the solution emerged as a pivotal factor influencing vesicle permeability. Fluorescence lifetime experiments further revealed discernible variations in the effect of sphingosine molecular structure on the mobility of hydrophobic regions within lipid bilayers. These observed distinctions emphasize the impact of molecular structure on intermolecular interactions, extending to the microscopic architecture of membranes, and underscore the significance of subtle alterations in molecular structure and their associated aggregation behaviors in governing membrane permeability.

Amino acid surfactants play a crucial role in many personal care products and pharmaceuticals. Their significance arises from their unique characteristics, including diverse molecular structures, low skin irritation, and excellent biodegradability. The structure of amino acid surfactants, particularly the structure of their hydrophobic chains, plays a pivotal role in determining their interfacial properties. It is proposed that the steric hindrance effect stemming from the presence of branched hydrophobic chains can exhibit a profound influence on both the interfacial adsorption behavior and the overall performance of amino acid surfactants. We synthesized a range of novel amino acid surfactants featuring varying lengths of branched chains, derived from natural terpenoid alcohols. Several characterization techniques, including surface tension measurements, dynamic light scattering, foam volume assessments, demulsification time evaluations, and contact angle measurements were used to reveal the substantial influence of branched chains and the chain length on the surfactant performance. The investigation shows how the presence of branched chains influences their interfacial properties, their propensity to form larger aggregates above the critical micelle concentration and the impact of pH on the surfactants performance. Within the examined pH range, surfactants featuring natural branched farnesol chains exhibit critical micelle concentration ranging from approximately 0.8 to 3.8 mM. Those values are significantly lower when compared to surfactants possessing similar length of linear chains. Simultaneously, the conversion of linear hydrophobic chains into branched chains enhances the foam stability promoted by the surfactants by approximately 10 %. These findings emphasize the collective impact of hydrophobic interactions and steric hindrance of the hydrophobic chains on surfactant surface packing. The distinctive interfacial behavior exhibited by branched surfactants shows great potential in establishing a theoretical foundation for formulation research in the development of highly efficient detergents and premium cosmetics.

The requirement for cryogenic supramolecular self-assembly of amphiphiles in subzero environments is a challenging topic. Here, the self-assembly of lamellar lyotropic liquid crystals (LLCs) are presented to a subzero temperature of -70 °C. These lamellar nanostructures are assembled from specifically tailored ultra-long-chain surfactant stearyl diethanolamine (SDA) in water/glycerol binary solvent. As the temperature falls below zero, LLCs with a liquid-crystalline Lα phase, a tilted Lβ phase, and a new folded configuration are obtained consecutively. A comprehensive experimental and computational study is performed to uncover the precise microstructure and formation mechanism. Both the ultra-long alkyl chain and head group of SDA play a crucial role in the formation of lamellar nanostructures. SDA head group is prone to forming hydrogen bonds with water, rather than glycerol. Glycerol cannot penetrate the lipid layer, which mixes with water arranging outside of the lipid bilayer, providing an ideal anti-freezing environment for SDA self-assembly. Based on these nanostructures and the ultra-low freezing point of the system, a series of novel cryogenic materials are created with potential applications in extremely cold environments. These findings would contribute to enriching the theory and research methodology of supramolecular self-assembly in extreme conditions and to developing novel anti-freezing materials.

Nonionic surfactant aerosols play a crucial role in many industries, but they can cause acute irritation to users’ eyes during spraying. This cytotoxic process is associated with corneal cell necrosis causing cell membrane disruption. Industrial grade surfactants are typically polydisperse mixtures described by their nominal chemical structure but how the polydispersity affects their interactions with cell membrane, remains largely unexplored. A better understanding could benefit product formulations to maximise their efficiency whilst minimising their toxicity to the users. In this study, poly-oxyethylene glycol monododecyl ethers (C12E4, C12E23) were used to form ideal binary surfactant mixtures. The cytotoxicities of mono and polydispersed surfactants towards human corneal epithelial cells were examined, followed by a series of biophysical characterisations of interactions between surfactants and model cell membranes. Notably, to probe the journey of individual C12E4 and C12E23 surfactant molecules across the cell membrane from a binary surfactant mixture, “two-colour” neutron reflection measurements were achieved via Hydrogen/Deuterium substitution. The relative distributions of C12E4 and C12E23 across cell membranes and their nanostructural conformations revealed a synergistic membrane-lytic ability initiated by surfactant mixing, with the more hydrophobic C12E4 exhibiting stronger membrane binding potency than the hydrophilic C12E23. The exact molar ratio of C12E4 against C12E23 in the mixture determined how the mixed surfactant interacted with the cell membrane, and how the process directly impacted cytotoxicity and eye irritation. Thus, the cytotoxicity of polydisperse surfactants is not the same as monodisperse surfactant of the same average structure. This work provides a useful basis for the assessment of surfactant mixing by balancing their efficiency and toxicity.

Investigating the molecular conformations of monoclonal antibodies (mAbs) adsorbed at the solid/liquid interface is crucial for understanding mAb solution stability and advancing the development of mAb-based biosensors. This study examines the pH-dependent conformational plasticity of a human IgG1k mAb, COE-3, at the SiO2/water interface under varying pH conditions (pH 5.5 and 9). By integrating neutron reflectivity (NR) and molecular dynamics (MD) simulations, we reveal that the mAb irreversibly deposits onto the interface at pH 5.5, with surface density saturation reached at 20 ppm bulk concentration. At pH 5.5, the adsorbed mAb adopts a stable "flat-on" orientation, while at pH 9, it assumes a more flexible conformation and a "tilted" orientation. This pH-dependent orientation shift is reversible and influenced by the distinct surface charge properties of the Fab and Fc fragments, with the Fc fragment more prone to desorption at higher pH. The root-mean-square deviation (RMSD) analysis further shows that COE-3 maintains structural stability upon adsorption across both pH levels, showing minimal unfolding or denaturation. These findings highlight how pH-dependent electrostatic interactions between mAb fragments and the SiO2 interface drive conformational adjustments in the intact mAb, offering insights into adsorption-induced aggregation and suggesting pH modulation as a mechanism for controlling biosensor efficiency.

The use of DEHP (diethylhexyl phthalate) is now banned for most applications in Europe; the exception is for blood bags, where its toxicity is overshadowed by its ability to extend the storage life of red blood cells. Another plasticiser, BTHC (butanoyl trihexyl citrate), is used in paediatric blood bags but does not stabilise blood cells as effectively. Interactions between plasticisers and lipids are investigated with a phospholipid, DMPC, to understand the increased stability of blood cells in the presence of DEHP as well as bioaccumulation and identify differences with BTHC. Mixed monolayers of DMPC and DEHP or BTHC were studied on Langmuir troughs where surface pressure/area isotherms can be measured. Neutron reflection measurements were made to determine the composition and structure of these mixed layers. A large amount of plasticiser can be incorporated into a DMPC monolayer but once an upper limit is reached, plasticiser is selectively removed from the interface at high surface pressures. The upper limit is found to occur between 40-60 mol% for DEHP and 20-40 mol% for BTHC. The areas per molecule are also different with DEHP being in the range of 50-100 angstrom 2 and BTHC being 65-120 angstrom 2. Results indicate that BTHC does not fit as well as DEHP in DMPC monolayers which could help explain the differences observed with regards to the stability of blood cells. The use of DEHP (diethylhexyl phthalate) is now banned for most applications in Europe; the exception is for blood bags, where its toxicity is overshadowed by its ability to extend the storage life of red blood cells.

Saturated C22-tailed ultra-long-chain imparts cationic surfactant stable chemical structure and strong hydrophobic interaction that favors the generation of wormlike micelles in brine. Such viscoelastic wormlike micellar fluid is expected to exhibit excellent salt-resistance and temperature-resistance. In this work, the self-assembled microstructures and microscopic flow properties of docosyl(trimethyl)aza-nium chloride (DCTAC) NaCl solutions were systematically investigated by means of cryogenic transmis-sion electron microscopy (cryo-TEM), rheo-small angle neutron scattering (rheo-SANS), steady-state and dynamic rheology. It is found that DCTAC forms long, linear or branched, flexible or stiff wormlike micelles depending on NaCl concentration. The increase in salt content simultaneously promotes the growth of worm length and the formation of branches. While the worm chain elongation plays a domi-nant role in mid-range of NaCl concentrations, the branching formation acts as a leading role in supper high NaCl concentrations, which results in rheological properties experiencing a significant increase fol-lowed by a certain decrease upon increasing NaCl content up to ti 20 wt%. Moreover, DCTAC shows much better thickening power than corresponding homologue surfactants bearing shorter hydrophobic tail in brine, and DCTAC solution also shows much better temperature-resistance than them. These findings are helpful to understand salt effect on cationic surfactant self-assemble behavior, and the relationship between microstructure and solution macroscopical properties.(c) 2023 Elsevier B.V. All rights reserved.

The rational design of lipid nanoparticles (LNPs) for enhanced gene delivery remains challenging because of incomplete knowledge of their formulation-structure relationship that impacts their intracellular behavior and consequent function. Small-angle neutron scattering has been used in this work to investigate the structure of LNPs encapsulating plasmid DNA upon their acidification (from pH 7.4 to 4.0), as would be encountered during endocytosis. The results revealed the acidification-induced structure evolution (AISE) of the LNPs on different dimension scales, involving protonation of the ionizable lipid, volume expansion and redistribution of aqueous and lipid components. A similarity analysis using an LNP's structural feature space showed a strong positive correlation between function (measured by intracellular luciferase expression) and the extent of AISE, which was further enhanced by the fraction of unsaturated helper lipid. Our findings reveal molecular and nanoscale changes occurring during AISE that underpin the LNPs' formulation-nanostructure-function relationship, aiding the rational design of application-directed gene delivery vehicles.

Interfacial adsorption of monoclonal antibodies (mAbs) can cause structural deformation and induce undesired aggregation and precipitation. Nonionic surfactants are often added to reduce interfacial adsorption of mAbs which may occur during manufacturing, storage, and/or administration. As mAbs are commonly manufactured into ready-to-use syringes coated with silicone oil to improve lubrication, it is important to understand how an mAb, nonionic surfactant, and silicone oil interact at the oil/water interface. In this work, we have coated a polydimethylsiloxane (PDMS) nanofilm onto an optically flat silicon substrate to facilitate the measurements of adsorption of a model mAb, COE-3, and a commercial nonionic surfactant, polysorbate 80 (PS-80), at the siliconized PDMS/water interface using spectroscopic ellipsometry and neutron reflection. Compared to the uncoated SiO2 surface (mimicking glass), COE-3 adsorption to the PDMS surface was substantially reduced, and the adsorbed layer was characterized by the dense but thin inner layer of 16 Å and an outer diffuse layer of 20 Å, indicating structural deformation. When PS-80 was exposed to the pre-adsorbed COE-3 surface, it removed 60 wt % of COE-3 and formed a co-adsorbed layer with a similar total thickness of 36 Å. When PS-80 was injected first or as a mixture with COE-3, it completely prevented COE-3 adsorption. These findings reveal the hydrophobic nature of the PDMS surface and confirm the inhibitory role of the nonionic surfactant in preventing COE-3 adsorption at the PDMS/water interface.