Addition Of Surfactant Research Articles

Intact NMR Approach Quickly Reveals Synchronized Microstructural Changes in Oil-in-Water Nanoemulsion Formulations

A soft-core oil-in-water (o/w) nanoemulsion (NE) is composed of nanometer (nm) sized oil droplets, stabilized by a surfactant layer and dispersed in a continuous bulky water phase. Characterization of the o/w NE molecule arrangements non-invasively, particularly the drug phase distribution (DPD) and its correlation to oil globule size (OGS), remains a challenge. Here we demonstrated the analytical methods of intact 19F Nuclear Magnetic Resonance (NMR) and 1H diffusion ordered spectroscopy (DOSY) NMR for their specificity in measuring DPD and OGS, respectively, on three NE formulations containing the active ingredient difluprednate (DFPN) at the same concentration. The results illustrated synchronized molecular rearrangement reflected in the DPD and OGS upon alterations in formulation. Addition of surfactant resulted in a higher DPD in the surfactant layer, and concomitantly smaller OGS. Mechanic perturbation converted most of the NE globules to the smaller thermodynamically stable microemulsion (ME) globules, changing both DPD and OGS to ME phase. These microstructure changes were not observed using 1D 1H NMR; and dynamic light scattering (DLS) was only sensitive to OGS of ME globule in mechanically perturbed formulation. Collectively, the study illustrated the specificity and essential role of intact NMR methods in measuring the critical microstructure attributes of soft-core NE systems quickly, accurately, and non-invasively. Therefore, the selected NMR approach can be a unique diagnostic tool of molecular microstructure or Q3 property in o/w NE formulation development, and quality assurance after manufacture process or excipient component changes.Graphical abstract

The effect of various crystalline forms of HFC 134a hydrate on the growth rate and desalination efficiency

Experimental studies on the synthesis of HFC 134a hydrate in the liquid HFC 134a – water system were performed. Despite today's lack of research on the use of HFC 134a hydrate for desalination of seawater and separation of harmful impurities by HFC 134a hydrate synthesis, this method has prospects for development: HFC 134a hydrate is synthesized at relatively high temperature and low pressure; it is poorly soluble in water, which simplifies gas hydrate separation from water–salt solution; it has high volumetric storage density and relatively high thermal conductivity. In spite of its low solubility in water, HFC hydrate exhibits relatively high growth rates. The growth of various crystalline forms and the peculiarities of their occurrence in pure water, aqueous salt solution, as well as with the addition of surfactant are considered. The use of SDS increases the HFC hydrate growth rate. For the first time, it was shown that the intensive growth of HFC 134a hydrate in the form of needles throughout the entire volume of the liquid allows increasing the efficiency of desalination. It is important to consider the desalination process comprehensively, taking into account the crystal forms, crystal growth rate, crystal defects, as well as taking into account the degree of salt removal. Simultaneously with the bubble growth, a thin gas hydrate film is shown to grow on the bubble surface. A detailed consideration of the stages of such hydrate growth is provided to explain the high-speed synthesis of porous HFC hydrate due to boiling of liquid HFC and vaporization.

Three-dimensionally oriented organization of hexagonal MIL-96 microplates toward superior film microstructure

Preferential orientation control of MOF films is advantageous for maximizing pore uniformity and minimizing grain boundary defects. Nonetheless, the preparation of MOF films with both in-plane and out-of-plane orientations remains a grand challenge. In this study, we reported the preparation of three-dimensionally oriented MIL-96 layers through combining morphology control of MIL-96 seeds with addition of PVP surfactants and arachidonic acids. Three-dimensionally oriented MIL-96 film was readily obtained through in-plane epitaxial growth. It is anticipated that the above protocol can be effective for obtaining diverse MOF films with three-dimensionally oriented organization.

The impact of cationic/anionic ratio on the physicochemical aspects of catanionic niosomes as a promising carrier for anticancer drugs

BackgroundNiosomes are adaptable nanocarriers for the delivery and controlled release of anticancer drugs. The addition of ionic surfactants could easily functionalize these carriers. Catanionic niosomes that are comprised of cationic and anionic surfactants are effective drug-delivery vehicles. Here, we aim to evaluate the impact of the cationic/anionic ratio on the noisome characteristics. MethodsA novel approach utilizing molecular modeling was utilized to analyze some characteristics of catanionic niosomes, showing great potential as a vehicle for anticancer drugs. The nonionic surfactant SPAN60, along with cholesterol as the stabilizer, was utilized in the study. Moreover, CTAB and SDS were used as positively and negatively charged surfactants, respectively. An FDA-approved c-Met inhibitor, cabozantinib, was selected as the drug. Several significant parameters associated with the cabozantinib molecule and its properties within the bilayer like hydrogen bonding, total energy, radius of gyration (Rgyr), diffusion coefficient, and radial distribution function (RDF). ResultsThe findings suggest that the cabozantinib’s hydrogen bonding plays a vital role in the drug’s movement through the bilayer. The CTAB-rich niosomes showed a higher number of hydrogen bonds compared to the SDS-rich formulations. The diffusion coefficient was in agreement with the number of H-bonding, and this value increased from 3.12 × 10-12 (m2/s) in CTAB-rich niosome to 7.66 × 10-12 (m2/s) in SDS-rich niosime. ConclusionThe total binding energy between the drug and bilayer components can control drug release. The computational approach could sufficiently describe the influence of cationic/anionic molar ratios on the bilayer features, and the characteristics of catanionic niosomes could be easily adjusted for the controlled release of anticancer drugs.

Pickering emulsion stabilized by cellulose nanofibril from pineapple leaves for biofoam manufacture

Cellulose nano fibril (CNF) can be selected as an agent of pickering emulsion in biofoam manufacture. This study thoroughly investigates the pickering emulsion method for producing biofoam, the characterization of CNF from pineapple leaves, the production of biofoam with various concentration of CNF and surfactant, and the effect of these parameters on the properties of wet foam and dry foam. CNF was created by mechanical grinding then the stability and morphology were evaluated. The pickering emulsion mechanism in biofoam manufacture was investigated using foamability and foam stability with various CNF and surfactant concentration. As the results, CNF concentrations will create varying zeta potential values. The morphology of CNF shows that it has a structure-like entangled network. The stability test demonstrates that adding CNF improves the stability and foamability of biofoam by the pickering effect. Biofoam without CNF has an unstable structure and is easily collapse when dried in an oven. The concentration of CNF and the amount of surfactant utilized altered the qualities of both wet and dry foam. The lower concentration of CNF and the addition of surfactant could increases foamability, high porosity, water absorption, and biodegradability; as well as low density, contact angle and bending characteristics. In biofoam that consists of 2 % CNF, the stability of wet foam increases as the amount of surfactant added, resulting in a biofoam with low tensile strength.

Effect of surfactants on lactate dehydrogenase aqueous solutions: A comparative study of poloxamer 188, polysorbate 20 and 80

The effect of three commonly used surfactants, poloxamer 188 (P188), polysorbate 20 and 80 (PS20 and PS80), on the stability of a model protein, lactate dehydrogenase (LDH), was compared in aqueous solutions. In the absence of a surfactant, protein solution revealed a gradual decrease in surface tension as a function of time. The addition of surfactant resulted in a rapid decrease in the surface tension. This suggested that the surface behavior was dictated by the surfactant. PS20 and PS80 were more effective than P188 in preventing LDH adsorption on the solution surface. The advantage of polysorbates over P188 was also evident from the higher LDH tetramer recovery after shaking (room temperature, 30 h), especially when the surfactants were used at concentrations ≤ 0.01% w/v. However, PS20 and PS80 accelerated protein unfolding during quiescent storage at 40 °C. Based on circular dichroism results, polysorbates perturbed the tertiary structure of LDH but not the secondary structure, while P188 did not impact the protein structure and stability. Polysorbates were more effective in stabilizing LDH against mechanical stress (shaking), but their adverse effects on protein conformational stability need to be carefully evaluated.

A fully degradable flexible membrane via green synthesis for highly effective separation of oil-water emulsions

Flexible membranes have attracted extensive attention in water treatment due to their outstanding plasticity, portability, and toughness. However, conventional flexible membranes are usually made from non-degradable polymers or hazardous reagents, posing threats to the environment. In this work, a flexible silica nanofiber-regenerated cellulose composite membrane was fabricated by “no polymer solvents electrospinning” with cellulose regeneration. The membrane was fully degradable and eco-friendly, and it exhibited low oil adhesion force and recyclable oil emulsion separation performance. It achieved removal rates of almost 100 % and up to 0.1 % residual oil rate for six different types of oil emulsions with the addition of surfactant, which represents the optimal level reported in the literature to date. The presence of these extremely water-attracting functional groups on the surface of the membrane allows them to bond with water molecules, creating a stable water layer held together by hydrogen bonds. This layer can reject oil compounds during the separation process due to the inherent immiscibility between water and oil. Importantly, this membrane has excellent degradability. The regenerated cellulose layer on its surface can undergo complete microbial degradation (activated sludge) within 7 days, while the remaining substrate can be degraded continuously in concentrated hydrochloric acid, thereby facilitating complete environmentally benign disposal and providing a new strategy for developing green flexible membranes, which holds promise for addressing water scarcity and water pollution issues.

Self-Assembly of Super-Uniform Covalent Organic Framework Colloidal Particles into Multi-Dimensional Ordered Superstructures.

Precise self-assembly of colloidal particles is crucial for understanding their aggregation properties and preparing macroscopic functional devices. It is currently very challenging to synthesize and self-assemble super-uniform covalent organic framework (COF) colloidal particles into well-organized multidimensional superstructures. Here, simple and versatile strategies are proposed for synthesis of super-uniform COF colloidal particles and self-assembly of them into 1D supraparticles, 2D ordered mono/multilayers, and 3DCOF films. For this purpose, several self-assembly techniques are developed, including emulsion solvent evaporation, air-liquid interfacial self-assembly, and drop-casting. These strategies enable the superstructural self-assembly of particles of varying sizes and species without any additional surfactants or chemical modifications. The assembled superstructures maintain the porosity and high specific surface area of their building blocks. The feasibility of the strategies is examined with different types of COFs. This research provides a new approach for the controllable synthesis of super-uniform COF colloidal particles capable of self-assembling into multidimensional superstructures with long-range order. These discoveries hold great promise for the design of emerging multifunctional COF superstructures.

Surfactant-assisted thermal hydrolysis of sewage sludge: Biomolecule extraction and its potential for protease production

Efficient management of sewage sludge from wastewater treatment plants (WWTPs) are crucial to obtain industrial value-added products and reducing environmental impact. Thermal hydrolysis, coupled with surfactants to enhance solubilisation, offers a promising approach for sewage sludge treatment. This study assessed the impact of four surfactants: sodium dodecyl sulphate (SDS), sodium dodecylbenzenesulfonate (SDBS), cetyl trimethyl ammonium chloride (CTAC), and tetraethylammonium chloride (TAC) on thermal hydrolysis of sewage sludge. The addition of anionic surfactants (SDS and SDBS) significantly increased biomolecule production, with proteins, humic-like substances, carbohydrates, and DNA concentrations reaching 6018 ± 28 mg/L (306 mg/gVSSo), 2496 ± 103 mg/L (127 mg/gVSSo), 1822 ± 4 mg/L (93 mg/gVSSo), and 389 ± 3 mg/L (20 mg/gVSSo), respectively, after 155 min of thermal hydrolysis. Low levels of surfactants (10 and 50 mg/gVSSo) also led to a substantial increase in the readily biodegradable fraction of hydrolysed sewage sludge, reaching up to 90 %. Additionally, surfactant-assisted hydrolysed sewage sludge proved to be a favourable substrate for protease production using Bacillus licheniformis. The optimal enzymatic activity of 678 ± 14 U/mL was achieved when CTAC was added at a concentration of 10 mg/gVSSo. In summary, this study evaluated an innovative approach to enhance the solubilisation of biomolecules from sewage sludge using surfactant-assisted thermal hydrolysis. This methodology not only positively affected biodegradability but also proved to be suitable for potentially producing valuable industrial products like proteases through fermentation with B. licheniformis, thus offering a new strategy for the sustainable treatment of sewage sludge.

Modelling the effect of soluble surfactants on droplet deformation and breakup in simple shear flow

A hybrid lattice Boltzmann and finite difference method is applied to study the influence of soluble surfactants on droplet deformation and breakup in simple shear flow. First, the influence of bulk surfactant parameters on droplet deformation in two-dimensional shear flow is investigated, and the surfactant solubility is found to influence droplet deformation by changing average interface surfactant concentration and non-uniform effects induced by non-uniform interfacial tension and Marangoni forces. In addition, the droplet deformation first increases and then decreases with Biot number, increases significantly with adsorption number $k$ and decreases with Péclet number or adsorption depth; and among the parameters, $k$ is the most influential one. Then, we consider three-dimensional shear flow and investigate the roles of surfactants on droplet deformation and breakup for different capillary numbers and viscosity ratios. Results show that in the soluble case with $k=0.429$ , the droplet exhibits nearly the same deformation as in the insoluble case due to the balance between surfactant adsorption and desorption; upon increasing $k$ from 0.429 to 1, the average interface surfactant concentration is greatly enhanced, leading to significant increase in droplet deformation. The critical capillary number of droplet breakup $C{{a}_{cr}}$ is identified for varying viscosity ratios in clean, insoluble and soluble ( $k=0.429$ and 1) systems. As the viscosity ratio increases, $C{{a}_{cr}}$ first decreases and then increases rapidly in all systems. The addition of surfactants always favours droplet breakup, and increasing solubility or $k$ could further reduce $C{{a}_{cr}}$ by increasing average interface surfactant concentration and local surfactant concentration near the neck during the necking stage.

Impact of surfactants on SWCNT dispersion in N-methylmorpholine N-Oxide for cellulose dissolution

A well dispersed slurry of single-walled carbon nanotube (SWCNT) and 60 % hydrated N-methylmorpholine N-oxide (NMMO) solution was prepared by probe sonicator. The proper dispersion of carbon nanotube (CNT) has been verified by optical microscope by varying the sonication time. Further, the slurry was concentrated to 76 % (for cellulose dissolution) and during this process some agglomeration of CNTs has been observed. The dispersion of CNT aggregation was checked by addition of surfactants like sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) (with 2 % (w/w) with respect to CNT) to the surface of CNT. SDBS is giving better dispersion as compared to SDS when the slurry is heated to obtain 76 % NMMO as checked by optical microscope and UV–Vis spectrophotometer to get quantitative amount of dispersed CNT. 88 % dispersion has been obtained in case of SDBS-assisted CNT after heating followed by centrifugation of the concentrated solution. Similarly, 78 % dispersion has been observed in case of SDS-assisted CNT and 46 % dispersion in case of CNT without any surfactant. The stronger dispersion ability of SDBS could improve its use for SWCNT separation in NMMO solution which can be used further for cellulose dissolution to prepare lyocell fiber.

Thermal and surface properties of AlZnO and surfactant-stabilized AlZnO nanofluids: Influence of sonication duration for heat transfer applications

Research into doped metal oxide nanofluids (NFs) has intensified due to recent breakthroughs in heat transfer applications. This study explores the thermophysical properties of Aluminum Zinc Oxide (AlZnO) at a 0.10 vol% concentration and surfactant-enhanced Aluminum Zinc Oxide (f@AlZnO) at concentrations of 0.05, 0.10, and 0.20 vol%. Experiments were conducted across a temperature range from 20 to 80°C. The study utilized various analytical techniques such as FT-IR, UV–visible spectroscopy, Powder XRD, SEM, and EDX to examine the effects of volume concentration and sonication duration on stability, particle size, thermophysical properties, contact angle, wettability, and surface tension. It was found that the thermal conductivity of AlZnO and f@AlZnO NFs increases with both volumetric concentration and temperature. Notably, surfactant inclusion significantly enhanced the stability of AlZnO NFs, achieving a high zeta potential after 160 minutes of sonication. The 0.10 vol% f@AlZnO NF displayed optimal stability at this sonication duration, while the 0.10 vol% AlZnO NF showed the smallest particle size distribution after just 20 minutes. Thermal conductivity enhancements of 5 %, 2.5 %, 2 %, and 1.9 % were observed for 0.10 vol% AlZnO NF and 0.05, 0.10, and 0.20 vol% f@AlZnO NFs, respectively. Additionally, at 200 minutes of sonication, the 0.05 vol% f@AlZnO NF demonstrated the lowest increase in specific heat capacity. The study also revealed that both surfactant addition and increasing volumetric concentration of AlZnO NFs reduced surface stress and contact angle values. In contrast, dynamic viscosity and density increased with higher nanoparticle concentration and decreased with rising temperature. The Mouromtseff number calculations underscore the potential of AlZnO NFs in thermal applications, meriting further investigation. This comprehensive examination provides critical insights into the effective utilization of hybrid metal oxide NFs in heat transfer applications.

New molecular and macroscopic understandings of novel green chemicals based on Xanthan Gum and bio-surfactants for enhanced oil recovery

This research investigates the interactions between a novel environmentally friendly chemical fluid consisting of Xanthan gum and bio-based surfactants, and crude oil. The surfactants, derived from various leaves using the spray drying technique, were characterized using Fourier-transform infrared (FTIR) spectroscopy, zeta potential analysis, Dynamic light scattering, and evaluation of critical micelle concentration. Static emulsion tests were conducted to explore the emulsification between crude oil and the polymer-surfactant solution. Analysis of the bulk oil FTIR spectra revealed that saturated hydrocarbons and light aromatic hydrocarbons exhibited a higher tendency to adsorb onto the emulsion phase. Furthermore, the increased presence of polar hydrocarbons in emulsion phases generated by polar surfactants confirmed the activation of electrostatic forces in fluid–fluid interactions. Nuclear magnetic resonance spectroscopy showed that the xanthan solution without surfactants had a greater potential to adsorb asphaltenes with highly fused aromatic rings, while the presence of bio-based surfactants reduced the solution's ability to adsorb asphaltenes with larger cores. Microfluidic tests demonstrated that incorporating surfactants derived from Morus nigra and Aloevera leaves into the xanthan solution enhanced oil recovery. While injection of the xanthan solution resulted in a 49.8% recovery rate, the addition of Morus nigra and Aloevera leaf-derived surfactants to the xanthan solution increased oil recovery to 58.1% and 55.8%, respectively.

Structure, magnetic properties and hyperthermia of Fe3-xCoxO4 nanoparticles obtained by wet high-energy ball milling

In this work, the methods of X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), magnetic properties measurements and specific loss measurements (hyperthermia) were used for the investigation of the structure and properties of Fe3-xCoxO4 nanoparticles. The Fe3-xCoxO4 nanoparticles were synthesized by using high-energy ball milling of Fe and Co mixed with water and surfactant additives. Co substitution increased the coercivity of the samples and changed the kinetics of oxidation process. The presence of cobalt ferrite was verified by MS. TEM images of synthesized samples demonstrated 5–50 nm particle size. Specific loss related heating effect depended mostly on the ratio between the samples coercivity and the amplitude of the high-frequency field. Specific loss power (SLP) and intrinsic loss power (ILP) values reached 164 W/g and 1.57 nH·m2/kg, respectively.

Studies on the inhibitory effect of different surfactants on ammonium chloride corrosion

Corrosion of heat exchangers by ammonium chloride (NH4Cl) is a common occurrence in the refineries. A variety of methods have been adopted to prolong the service life of equipment in such circumstances, such as the use of various additives such as surfactants or by washing with water. In this paper, a series of experiments are performed to investigate the effects of different surfactants (cationic, anionic, amphoteric, and nonionic) on NH4Cl corrosion using the sessile drop technique and electrochemical measurements. The results show that the presence of a surfactant can increase the wettability of an NH4Cl solution, decreasing the contact angle between the solution and a test material. The surface tension of an NH4Cl solution containing an anionic surfactant is the lowest, but the self-corrosion potential of such a solution is the greatest. The addition of a cationic surfactant has no inhibitory effect on corrosion, and indeed increases the corrosion rate. However, with a nonionic surfactant, it is possible to significantly decrease the corrosion rate of an NH4Cl solution, although the inhibitory effect decreases with increasing temperature.

Removal of empty capsids from high-dose adeno-associated virus 9 gene therapies.

Recombinant adeno-associated virus, serotype 9 (rAAV9) has shown promise as a gene therapy vector for muscle and central nervous diseases. High-dose requirements of these therapies present critical safety considerations and biomanufacturing challenges. Notably, the reduction of empty capsids (ECs), which lack therapeutic transgene, from rAAV9 products is critical to maximize efficacy. Removal of rAAV ECs from full capsids is a major downstream challenge because of their highly similar biophysical characteristics. Ultracentrifugation (UC) reduces ECs but is laborious and difficult to scale. In this paper, to replace a poorly scalable UC process, we developed an anion exchange (AEX) chromatography for rAAV9 EC reduction from full capsids. AEX load preparation by dilution incurred major product loss. The addition of histidine and surfactants to dilution buffers increased yield and reduced aggregation. Elution salts were screened and sodium acetate was found to maximize yield and EC reduction. The most promising load dilution buffer and elution salt were used in combination to form an optimized AEX method. The process reduced ECs three-fold, demonstrated robustness to a broad range of EC load challenges, and was scaled for large-scale manufacture. Compared to UC, the AEX method simplified scale-up, reduced ECs to comparable levels (20%), afforded similar purity and product quality, and increased yield by 14%.

Applying machine learning to reveal the microscopic heat transfer mechanism of nanofluids as coolants

Nanofluids are considered as excellent coolants to optimize thermal management of electronic devices, where the nanoparticle morphology and the addition of surfactants can affect the thermal transport performance of nanofluids. Due to the limitations of high economic and computational cost in previous experimental and numerical simulation methods, the design of nanofluids urges for more efficient approaches. In this work, a novel machine learning framework coupled with molecular dynamics methods was proposed to model the multi-component mixing nanofluidic systems and explore the deep heat transfer mechanisms. Multi-input attribute point cloud dataset, dual channel sampling network and multi-nanoscale optimization scheme were used to improve the prediction performance of machine learning. The computational cost of the machine learning method is shortened by 36000 times compared with simulation methods. Moreover, our work can achieve up to 90 % prediction accuracy for surfactant adsorption properties. Furthermore, algorithm optimization strategy can improve the prediction accuracy of nanofluidic heat transfer performance by 40 %. The proposed framework has the potential to shorten the development cycle of nanofluidic design.

Effect of Edge Activator Combinations in Transethosomal Formulations for Skin Delivery of Thymoquinone via Langmuir Technique

Thymoquinone (TQ), a bioactive compound found in Nigella sativa seeds, possesses diverse therapeutic properties for skin conditions. However, formulating TQ presents challenges due to its hydrophobic nature and chemical instability, which hinder its skin penetration. Transethosomes, as a formulation, offer an environment conducive to enhancing TQ’s solubility, stability, and skin permeation. To optimize TQ transethosomal formulations, we introduced a combination of ionic and nonionic surfactants, namely Tween 20 and sodium lauryl sulfate (SLS) or sodium lauroyl glutamate (SLG). Surfactants play a crucial role in stabilizing the formulation, reducing aggregation, improving biocompatibility, and minimizing potential toxicity. We fine-tuned the formulation composition and gained insights into its interfacial behavior using the Langmuir monolayer technique. This method elucidated the interfacial properties and behavior of phospholipids in ethosome and transethosome formulations. Our findings suggest that monolayer studies can serve as the initial step in selecting surfactants for nanocarrier formulations based on their interfacial dilational rheology studies. It was found that the addition of surfactant to the formulation increased the elasticity considering the capability of transethosomes to significantly decrease their radius when permeating the skin barrier. The results of the dilational rheology experiments were most relevant to drug permeation through the skin for the largest amplitude of deformation. The combination of Tween 20 and SLS efficiently modified the rheological behavior of lipids, increasing their elasticity. This conclusion was supported by in vitro studies, where formulation F2 composed of Tween 20 and SLS demonstrated the highest permeation after 24 h (300.23 µg/cm2). Furthermore, the F2 formulation showed the highest encapsulation efficiency (EE) of 94%, surpassing those of the control and ethosomal formulations. Additionally, this transethosomal formulation exhibited antimicrobial activity against S. aureus, with a zone of inhibition of 26.4 ± 0.3 mm. Importantly, we assessed the cytotoxicity of both ethosomes and transethosomes at concentrations ranging from 3.5 µM to 50 µM on HaCaT cell lines and found no cytotoxic effects compared to TQ hydroethanolic solution. These results suggest the potential safety and efficacy of TQ transethosomal formulations.

Flexible, Photonic Films of Surfactant‐Functionalized Cellulose Nanocrystals for Pressure and Humidity Sensing

Most paints contain pigments that absorb light and fade over time. A robust alternative can be found in nature, where structural coloration arises from the interference of light with submicron features. Plant‐derived, cellulose nanocrystals (CNCs) mimic these features by self‐assembling into a cholesteric liquid crystal that exhibits structural coloration when dried. While much research has been done on CNCs in aqueous solutions, less is known about transferring CNCs to apolar solvents that are widely employed in paints. This study uses a common surfactant in agricultural and industrial products to suspend CNCs in toluene . Surprisingly, a stable liquid crystal phase is formed within hours, even with concentrations of up to 50 wt%. Evaporating the apolar CNC suspensions results in photonic films with peak wavelengths ranging from 660 to 920 nm. The resulting flexible films have variable mechanical properties with surfactant content, allowing for an optical response with applied force. The films also act as humidity sensors, with increasing relative humidity swelling the films, yielding a redshift in the reflected wavelength. With the addition of a single surfactant, CNCs can be made compatible with existing production methods of industrial coatings, while improving the strength and responsiveness of structurally colored films to external stimuli.

A Review of Methods to Modify the PDMS Surface Wettability and Their Applications.

Polydimethylsiloxane (PDMS) has attracted great attention in various fields due to its excellent properties, but its inherent hydrophobicity presents challenges in many applications that require controlled wettability. The purpose of this review is to provide a comprehensive overview of some key strategies for modifying the wettability of PDMS surfaces by providing the main traditional methods for this modification and the results of altering the contact angle and other characteristics associated with this property. Four main technologies are discussed, namely, oxygen plasma treatment, surfactant addition, UV-ozone treatment, and the incorporation of nanomaterials, as these traditional methods are commonly selected due to the greater availability of information, their lower complexity compared to the new techniques, and the lower cost associated with them. Oxygen plasma treatment is a widely used method for improving the hydrophilicity of PDMS surfaces by introducing polar functional groups through oxidation reactions. The addition of surfactants provides a versatile method for altering the wettability of PDMS, where the selection and concentration of the surfactant play an important role in achieving the desired surface properties. UV-ozone treatment is an effective method for increasing the surface energy of PDMS, inducing oxidation, and generating hydrophilic functional groups. Furthermore, the incorporation of nanomaterials into PDMS matrices represents a promising route for modifying wettability, providing adjustable surface properties through controlled dispersion and interfacial interactions. The synergistic effect of nanomaterials, such as nanoparticles and nanotubes, helps to improve wetting behaviour and surface energy. The present review discusses recent advances of each technique and highlights their underlying mechanisms, advantages, and limitations. Additionally, promising trends and future prospects for surface modification of PDMS are discussed, and the importance of tailoring wettability for applications ranging from microfluidics to biomedical devices is highlighted. Traditional methods are often chosen to modify the wettability of the PDMS surface because they have more information available in the literature, are less complex than new techniques, and are also less expensive.