Determination Of Contact Angle Research Articles

3DDA: A Novel Python Toolkit to Analyze 3D‐Dynamic Contact Angles from Molecular Dynamics Simulations

Obtaining fast and reliable contact angles in molecular dynamics simulations is crucial for screening surface wettability. Traditional methods rely on bidimensional density profile analysis to localize the liquid/vapor interface, which may not be optimal at the nanoscale, especially for nonsymmetrical droplets. Herein, 3DDA, a Python‐based code that uses the 3D droplet geometry to determine contact angles and analyze dynamic changes during spreading processes at the nanoscale, is presented. The 3D density profile of liquid molecules is enveloped using the Euclidean 3D convex hull algorithm to locate the contact line at the solid‐, liquid‐, and vapor‐phase boundaries. By fitting a general ellipsoidal function and optimizing it with the limited‐memory Broyden–Fletcher–Goldfarb–Shanno method, the best candidate function is analytically obtained, describing the interface. The angle derived from the ellipsoidal function and the solid boundary is used to gather a collection of contant angles, which are then fed into a kernel density estimator to determine the most probable angle along the contact line during the spreading process. This methodology is tested on systems such as liquid water and metals, demonstrating its efficacy and reliability. Herein, valuable insights are provided into the behavior of liquids, considering droplet asphericity induced by liquid/solid interactions.

Effect of plasma-activated water on the settling characteristics of ultrafine kaolinite

Coal slurry water is a complex multiphase system, and its settling characteristics are influenced not only by the solid phase coal slime but also by the liquid phase water. This paper firstly explores the effect of plasma-activated water (PAW) on the settling of ultrafine kaolinite through settling experiments, turbidity tests & dynamic observations. The findings show that PAW significantly improves the settling behavior of ultrafine kaolinite, manifested by an increased settling velocity, higher final settling height, shorter settling end time, and reduced turbidity of the supernatant. Furthermore, the potential mechanisms by which PAW enhances the settling of ultrafine kaolinite are analyzed through laser particle size detections, fractal dimension calculations, zeta potential measurements & contact angle determinations. The mechanism analysis indicates that PAW not only reduces the electrostatic repulsion of ultrafine kaolinite particles but also enhances the hydrophobicity, thereby increasing both the size and density of ultrafine kaolinite flocs, which improves the settling performance of ultrafine kaolinite. This study not only provides new insights for enhancing ultrafine kaolinite settling with PAW but also offers new approaches for the efficient settling of coal slurry water.

An analytical approach for determining contact angle hysteresis on smooth, micropillared, and micropored homogeneous surfaces

HypothesisNumerous theoretical models have been developed from various research perspectives, including free energy analysis, force balance, and contact line dynamics, to elucidate the contact angle hysteresis on solid surfaces, especially for superhydrophobic surfaces. However, these models can produce inconsistent predictions, and few of them account for contact angle hysteresis on smooth and microstructured surfaces simultaneously. TheoryFormulas for advancing and receding free energy barriers of drops on different solid surfaces were derived, and then these formulas were simplified by incorporating the geometric constraint equation of drops, leading to an establishment of analytical models. FindingsThis study presented a unified approach for deriving analytical models of contact angle hysteresis for various wetting systems, including drops on smooth homogeneous surfaces, Cassie drops on micropillared and micropored homogeneous surfaces, and Wenzel drops on micropillared homogeneous surfaces. The established models revealed a significant impact of frictional tension, and of the change in free energy during drop motion, on the free energy barriers. These models were fully derived thermodynamically without subsequent theoretical modifications and found to agree well with experimental results. Some of the models in this study were validated using other existing models, despite the models having been developed using completely different approaches.

Analysis of the competitive influence of gas adsorption and interface modification on the surface free energy of coal matrix

Coal is a complex porous medium characterized by numerous pores and fractures within its internal structure, which provide a natural space for the storage of coalbed methane. The high surface free energy of coal significantly inhibits the efficient extraction of coalbed methane, resulting in the escape of considerable amounts of greenhouse gas during the later stages of coal mining. This exacerbates the challenges and costs associated with environmental governance. According to the principle of minimum capacity, the surface of the coal matrix reduces its surface free energy through gas adsorption. To investigate the competitive influence of gas adsorption and interface modification on the surface free energy of the coal matrix, isothermal adsorption and contact angle determination experiments were conducted. The results indicate that as equilibrium pressure increases, the amount of gas adsorption on the surface of the coal matrix also increases, while the adsorption potential exhibits a contrasting trend. Under the influence of gas adsorption, there is a significant increase in Gibbs variation, indicating a substantial decrease in the surface free energy of the coal matrix. Under the influence of interface modification, an increase in surfactant concentration resulted in a trend of energy reduction characterized by an initial increase followed by a subsequent decrease. Moreover, interface modification effectively eliminated the water-blocking effect, leading to a significant enhancement in gas desorption. Consequently, interface modification offers important theoretical support for improving production in coalbed methane and mitigating the greenhouse effect.

Wetting characterisation on complex surfaces by an automatic open-source tool: DropenVideo

HypothesisInvestigating solid–liquid interactions to determine advancing and receding contact angles, and consequently contact angle hysteresis, is crucial for understanding material wetting properties. A reliable, automated, and possibly open-source tool is desirable, to standardize and automatize the measurement and make it user-independent. ExperimentsThis study introduces an open-source software, DropenVideo, as an extension of Dropen. DropenVideo automates frame-by-frame video analysis for the advancing and receding contact angle determination, by considering needle presence, contrast tuning, and compensating for missing drop edge data. Contact angles are calculated using convolution mask, circle, and polynomial fittings. An innovative feature in DropenVideo is the automatic protocol for identifying advancing and receding contact angles: (i) the advancing contact angle is determined as the average value during drop inflation; and (ii) the receding contact angle is determined from the frame of incipient motion during drop deflation. FindingsExploring the application of DropenVideo across a range of complex surfaces as representative test cases, we highlight existing challenges in interpreting wetting measurements by addressing different wetting scenarios. Our study demonstrates that employing frame-by-frame automatic analysis of contact angle measurement videos using DropenVideo significantly mitigates the potential risks of subjective bias associated with manual interpretation and enhances the precision of identified wetting characteristics.

Essential oils loaded carboxymethylated Cassia fistula gum-based novel hydrogel films for wound healing

Carboxymethylated Cassia fistula gum (CCFG) and citric acid (CA) based wound healing film, (CCFG-CA) was developed using the solvent casting method. Glycerol was added as a plasticizing agent. The synthesized Carboxymethylated Cassia fistula gum cross-linked citric acid based hydrogel film (CCFG-CA) was evaluated morphologically, thermally, and structurally using FESEM, TGA, XRD and FTIR. Three essential oils (EO), rosemary (Rosmarinus officinalis), turmeric (Curcuma longa) and thuja (Thuja occidentalis L), known for antimicrobial and antioxidant activities, were loaded into the CCFG-CA film to develop essential oils loaded carboxymethylated Cassia fistula gum cross-linked citric acid based hydrogel film (CCFG-CA-EO). In vitro studies (MTT assay, disk diffusion assay, permeability tests and DPPH assay) confirm the biocompatibility, anti-oxidant and anti-microbial properties of the CCFG-CA-EO film. In vivo (wound healing studies on wistar rats and their histology) shows 99 % of wound healing and re-epithelialization in 14 days. Degradability (within 15 days), protein adsorption (12.05 μg/mL) and contact angle determination (69.43°ׄׄ ± 0.48) tests confirmed the potential of CCFG-CA-EO as an effective wound-healing material.

Cocrystal of Lutein with Improved Stability and Bioavailability.

Lutein (LT) is a natural carotenoid and is widely used for its vision protection and antioxidant activity. However, the long-chain polyene structure makes lutein sensitive to light and oxygen and poses many difficulties in the production, processing, and storage. In addition, the special chemical structure of LT leads to low solubility and bioavailability. In this study, we propose an efficient solution to address these issues. A cocrystal of LT with adipic acid (LT-APC) was obtained for the first time. The cocrystals were fully characterized. After cocrystallization, the melting point of marketed LT was increased. The chemical stability of LT was significantly improved, and the influence of impurities on stability was limited. Dissolution experiments were performed in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) and the cocrystal generated a much higher apparent solubility. To deepen insight into the mechanisms underlying the cocrystal's improved solubility, wettability tests were performed by contact angle determination and film flotation methods. The cocrystal presented better wettability than the marketed LT. Finally, pharmacokinetic studies of marketed LT and its cocrystal were conducted in rats. The results showed that the cocrystal exhibited 3.4 times higher C max and 2.2 times higher AUC at a single dose compared with marketed LT.

Electrospun poly(ɛ‐caprolactone) membranes modified with heparin and essential fatty acids for biomedical applications

AbstractThis study aimed to modify poly(ε‐caprolactone) (PCL) membranes with sodium heparin (SH) and essential fatty acids (EFA) for later application in wound healing. The electrospinning technique was used to prepare the membranes containing the maximum concentration of SH and EFA, which were then sterilized with ozone. Microbiological tests confirmed effective sterilization. The membrane characterization included scanning electron microscopy for morphological analysis, contact angle determination for wettability studies, Fourier‐transform infrared spectroscopy (FT‐IR) analysis, and thermogravimetry for thermal analysis. Results indicated that the average diameter membrane of PCL, PCL + SH, and PCL + EFA nanofibers was 1.16 ± 0.99 μm, 0.98 ± 0.66 μm and 1.53 ± 0.92 μm, respectively. Adding SH and EFA affected the fiber diameter, with PCL + SH fibers having a smaller diameter than pure PCL and PCL + EFA fibers. The contact angle of the membrane is 123° (PCL), 102° (PCL + SH), and 95° (PCL + EFA). Wettability analysis demonstrated modified surface properties with reduced contact angles. Sterilization of PCL membranes modified with SH and EFA has shown effectiveness in eliminating bacteria and other microorganisms, increasing the permeability of the membranes. Morphological analysis showed well‐formed and randomly distributed fibers, although the PCL + SH membrane exhibited beads on its fibers. FT‐IR analysis showed slight contributions of SH and EFA in the modified PCL membranes, while thermal analysis revealed no substantial changes in thermal stability. In conclusion, PCL membranes modified with SH and EFA can potentially accelerate wound healing, presenting an innovative and cost‐effective approach to treating skin injuries.

Moisture damage resistance of pyro-oil modified bitumen with hydrated lime using surface free energy approach

Moisture damage (MD) in bituminous mixtures occurs due to the loss of cohesion in the bitumen or adhesion between the binder and aggregates. The existence of moisture may influence the bonding between aggregates and bitumen, which may affect the moisture susceptibility of the bituminous mix. Therefore, there is a need to understand the bonding-debonding properties and the moisture susceptibility of binders and mixes, at the material selection stage. Surface free energy (SFE) method is one of the proven techniques to quantify the moisture susceptibility of bituminous mixtures, by using contact angle (CA) determination of the component materials of the mix. This study aimed to evaluate the effect of hydrated lime (HL) on the moisture susceptibility of bituminous mixtures, with control (VG30) bitumen and pyro-oil modified bitumen (POMB) having different percentages of pyro oil, using the SFE approach. Also, the study compared the SFE characteristics of VG30 and POMB with and without the optimum content of HL. POMB binders were prepared by the addition of high-density polyethylene (HDPE) pyro oil in percentages of 1, 3, and 5% in a control bitumen. HL was added as 20%, 25%, and 30% by weight of bitumen in VG30 and POMB bitumen. The aggregates used in the study were limestone, basalt, gravel, and their SFE components were directly considered from the literature. The sessile drop method was used to measure the CA of bitumen and, in turn, determine the various SFE parameters using Van Oss–Chaudhury–Good theory. The moisture susceptibility of mixtures with and without HL was evaluated and compared. From the results, the MD resistance of the bituminous mixtures with modified and unmodified bitumen was found to be increased after the optimum of HL, depending upon the type of aggregates used. Basalt has a 27.41%, 23.38%, and 10.48% greater energy ratio (ER) with POMB1/25, POMB3/25, and POMB5/30, respectively, than VG30/30, the highest ER in modified base bitumen. This indicates that HDPE pyro-oil treatment improves MD resistance for basalt. Whereas for limestone and gravel, VG30/30 gives a maximum value of ER as compared to any other combination of HL modified POMB. The ER values would assist highway agencies in selecting the most compatible binder–aggregate combinations.

Reliable Determination of Contact Angle from the Liquid Fence.

Traditional methods of measuring contact angles often face difficulties in precisely defining the three-phase contact points. A novel method for accurately defining three-phase contact points based on liquid fences is proposed in this article. The tested liquid is placed in a cubic liquid fence composed of a pair of narrow strips of the tested solid and a pair of transparent wide strips. The transparent wide strip serves as the measurement window, and the surface tension of the liquid on it can be almost ignored. In experimental measurements, the horizontal coordinates of the end points of the liquid profile are fixed by the liquid fence, thus determining the horizontal coordinates of the three-phase contact points, which helps to accurately survey the contact angle. Additionally, since the parameters of the liquid fence are known, the size of the contact angle can also be calculated by measuring the height of the liquid level dome inside the liquid fence. Using the electric wetting effect as an example, we experimentally extracted a series of liquid contour maps with circular tops and square columns under varying voltages. The relationship curve between contact angle and voltage variation was obtained using the above methods, and a contact angle variation tendency seemed to agree well with the theoretical value.

Selective flotation of galena and sphalerite using N-(phosphonomethyl) iminodiacetic acid as an eco-friendly depressant

This study explored the use of N-(phosphonomethyl) iminodiacetic acid (PMIDA) as an eco-friendly depressant for the selective flotation of galena and sphalerite. Microflotation tests were performed to assess the effectiveness of PMIDA. Moreover, the depression mechanism of PMIDA was analyzed through solution chemistry calculations, zeta potential measurements, contact angle determination, X-ray photoelectron spectroscopy, and density-functional theory calculations. Solution chemistry calculations revealed that the presence of PMIDA as PMIDA3− ions in the pulp optimized the depressive effect on sphalerite. Additionally, contact angle results indicated a significant improvement in the surface hydrophilic of sphalerite after PMIDA treatment. Zeta potential measurements revealed that the adsorption capacity of xanthate on the sphalerite surface after PMIDA treatment significantly decreased. X-ray photoelectron spectroscopy analyses indicated that the adsorption of PMIDA on the sphalerite surface was associated with the phosphate functional groups of PMIDA. Density-functional theory simulation data indicated preferential adsorption of PMIDA on the sphalerite surface. These results indicate the potential of PMIDA as a promising depressant to inhibit the flotation of sphalerite and facilitate the selective flotation of galena.

Catalyst-Free Amino-Yne Click Reaction: An Efficient Way for Immobilizing Amoxicillin onto Polymeric Surfaces.

Surface modifications play a crucial role in enhancing the functionality of biomaterials. Different approaches can be followed in order to achieve the bioconjugation of drugs and biological compounds onto polymer surfaces. In this study, we focused on the immobilization of an amoxicillin antibiotic onto the surface of poly-L-lactic acid (PLLA) using a copper-free amino-yne click reaction. The utilization of this reaction allowed for a selective and efficient bioconjugation of the amoxicillin moiety onto the PLLA surface, avoiding copper-related concerns and ensuring biocompatibility. The process involved sequential steps that included surface activation via alkaline hydrolysis followed by an amidation reaction with ethylendiamine, functionalization with propiolic groups, and subsequent conjugation with amoxicillin via a click chemistry approach. Previous amoxicillin immobilization using tryptophan and fluorescent amino acid conjugation was carried out in order to determine the efficacy of the proposed methodology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), Attenuated Total Reflection (ATR)-Fourier Transform Infrared (FTIR) spectroscopy, surface imaging, water contact angle determination, and spectroscopic analysis confirmed the successful immobilization of both tryptophan and amoxicillin while maintaining the integrity of the PLLA surface. This tailored modification not only exhibited a novel method for surface functionalization but also opens avenues for developing antimicrobial biomaterials with improved drug-loading capacity.

Spatial Characterization of Wetting in Porous Media Using Local Lattice-Boltzmann Simulations

Wettability is one of the critical parameters affecting multiphase flow in porous media. The wettability is determined by the affinity of fluids to the rock surface, which varies due to factors such as mineral heterogeneity, roughness, ageing, and pore-space geometry. It is well known that wettability varies spatially in natural rocks, and it is still generally considered a constant parameter in pore-scale simulation studies. The accuracy of pore-scale simulation of multiphase flow in porous media is undermined by such inadequate wettability models. The advent of in situ visualization techniques, e.g. X-ray imaging and microtomography, enables us to characterize the spatial distribution of wetting more accurately. There are several approaches for such characterization. Most include the construction of a meshed surface of the interface surfaces in a segmented X-ray image and are known to have significant errors arising from insufficient resolution and surface-smoothing algorithms. This work presents a novel approach for spatial determination of wetting properties using local lattice-Boltzmann simulations. The scheme is computationally efficient as the segmented X-ray image is divided into subdomains before conducting the lattice-Boltzmann simulations, enabling fast simulations. To test the proposed method, it was applied to two synthetic cases with known wettability and three datasets of imaged fluid distributions. The wettability map was obtained for all samples using local lattice-Boltzmann calculations on trapped ganglia and optimization on surface affinity parameters. The results were quantitatively compared with a previously developed geometrical contact angle determination method. The two synthetic cases were used to validate the results of the developed workflow, as well as to compare the wettability results with the geometrical analysis method. It is shown that the developed workflow accurately characterizes the wetting state in the synthetic porous media with an acceptable uncertainty and is better to capture extreme wetting conditions. For the three datasets of imaged fluid distributions, our results show that the obtained contact angle distributions are consistent with the geometrical method. However, the obtained contact angle distributions tend to have a narrower span and are considered more realistic compared to the geometrical method. Finally, our results show the potential of the proposed scheme to efficiently obtain wettability maps of porous media using X-ray images of multiphase fluid distributions. The developed workflow can help for more accurate characterization of the wettability map in the porous media using limited experimental data, and hence more accurate digital rock analysis of multiphase flow in porous media.

Aging of Plasma-Activated Polyethylene and Hydrophobic Recovery of Polyethylene Polymers.

Available literature on the aging of plasma-activated polyethylene due to hydrophobic recovery has been reviewed and critically assessed. A common method for the evaluation of hydrophobic recovery is the determination of the static water contact angle, while the surface free energy does not reveal significant correlations. Surface-sensitive methods for the characterization of chemical composition and structure have limited applicability in studying the aging phenomenon. Aging is driven by thermodynamics, so it is observed even upon storage in a vacuum, and hydrophobic recovery increases with increasing temperature. Storage of plasma-activated polyethylene in the air at ambient conditions follows almost logarithmic behavior during the period studied by most authors; i.e., up to one month. The influence of the storage medium is somehow controversial because some authors reported aging suppression by storing in polar liquids, but others reported the loss of hydrophilicity even after a brief immersion into distilled water. Methods for suppressing aging by hydrophobic recovery include plasma treatment at elevated temperature followed by brief treatment at room temperature and application of energetic ions and photons in the vacuum ultraviolet range. Storing at low temperatures is a trivial alternative, but not very practical. The aging of plasma-activated polyethylene suppresses the adhesion of many coatings, but the correlation between the surface free energy and the adhesion force has yet to be addressed adequately.

Segmentation of two-phase flow X-ray tomography images to determine contact angle using deep autoencoders

This study improves the characterization of in situ contact angles in porous media by employing deep learning techniques (SegNet, UNet, ResNet, and UResNet) for multiphase segmentation of micro-CT images. The algorithms were tested on high-resolution X-ray images of a steady-state flow experiment where two fluid phases were simultaneously injected at different fractional flows. The models were trained to segment the images into solid, aqueous phase, and non-aqueous phase liquid (NAPL). The UResNet demonstrated the best performance with an f1-score of 0.966 for the test dataset. More importantly, the UResNet offered higher reliability than the watershed algorithm for various fractional flows based on visual inspection and phase distribution analysis. The porosity calculation error of the watershed method (7.8 %) was reduced to 5.1 % by UResNet. Furthermore, UResNet accurately depicted the consistently mixed-wet condition of the rock sample throughout the experiment, in contrast to the watershed segmentation that yielded inconsistencies in contact angle calculations at an aqueous phase fractional flow of 0.01.

Hydrophobicity of molecular-scale textured surfaces: The case of zeolitic imidazolate frameworks, an atomistic perspective.

Hydrophobicity has proven fundamental in an inexhaustible amount of everyday applications. Material hydrophobicity is determined by chemical composition and geometrical characteristics of its macroscopic surface. Surface roughness or texturing enhances intrinsic hydrophilic or hydrophobic characteristics of a material. Here we consider crystalline surfaces presenting molecular-scale texturing typical of crystalline porous materials, e.g., metal-organic frameworks. In particular, we investigate one such material with remarkable hydrophobic qualities, ZIF-8. We show that ZIF-8 hydrophobicity is driven not only by its chemical composition but also its sub-nanoscale surface corrugations, a physical enhancement rare amongst hydrophobes. Studying ZIF-8's hydrophobic properties is challenging as experimentally it is difficult to distinguish between the materials' and the macroscopic corrugations' contributions to the hydrophobicity. The computational contact angle determination is also difficult as the standard "geometric" technique of liquid nanodroplet deposition is prone to many artifacts. Here, we characterise ZIF-8 hydrophobicity via: (i) the "geometric" approach and (ii) the "energetic" method, utilising the Young-Dupré formula and computationally determining the liquid-solid adhesion energy. Both approaches reveal nanoscale Wenzel-like bathing of the corrugated surface. Moreover, we illustrate the importance of surface linker termination in ZIF-8 hydrophobicity, which reduces when varied from sp3 N to sp2 N termination. We also consider halogenated analogues of the methyl-imidazole linker, which promote the transition from nanoWenzel-like to nanoCassie-Baxter-like states, further enhancing surface hydrophobicity. Present results reveal the complex interface physics and chemistry between water and complex porous, molecular crystalline surfaces, providing a hint to tune their hydrophobicity.

CHARACTERIZATION AND SCREENING PARAMETERS OF SPRAY FILM-FORMING SYSTEMS: A COMPREHENSIVE STUDY ON DOSAGE FORMS AND QUALITY INDICATORS

Objective: The objective of this study is to present the main screening parameters for the development of Spray Film-Forming Systems (SFFSs) using the design space. The focus is on characterizing the different phase states of SFFSs during application and establishing appropriate methods for determining the range of parameters. Methods: In this study, various methods were used to determine the range of SFFS parameters. These include contact angle determination, pH test, viscosity measurement, drying rate estimation, spray pattern determination, tensile strength test, and washability. The methods used were evaluated and found to be effective in assessing the quality parameters of liquid concentrates, aerosols, and films of commercially available SFFS samples. Results: Three states (liquid, aerosol, and solid) of commercially available SPSFs were evaluated using the techniques mentioned above. The applicability of the techniques and variability was discussed in comparison with similar studies. The results showed that the mean pH ranged from 5.43±0.02 to 6.63±0.05, the bioadhesion of liquid concentrates was in a narrow range of 4.49±0.52, the highest index of dynamic viscosity was 0.33±0.04, values of the spray pattern ranged from 6.19±1.97 to 17.46±2.72 cm2, bioadhesion values of the films ranged from 3.87 to 4.06 N, average values of film formation time were in the range of 65.55±12.65) s. 3 of the 4 samples had resistance to skin cracking, the tensile load of the commercial SFFS films varied from 2.91±0.3 to 5.11±0.65 N, and the tensile strength from 1.07±0.11 to 1.20±0.3 mPa. All films were not washed off with water. Conclusion: The findings of this study demonstrate the successful application of tested methods in determining the range of parameters for SFFSs. The established values for indicators of liquid concentrates can serve as a basis for the further development of SFFSs. Overall, this research contributes to the understanding and standardization of Spray Film-Forming Systems for wounds, enabling their effective development and application in local skin treatments.

Study on modified VAc-VeoVa10 latex prepared by soap-free emulsion polymerization

Modified latex is prepared via the soap-free emulsion polymerization of ethyl acetate (VAc) and vinyl versatate (VeoVa10). DFHMA is used as modified monomers. The composite surfactants of SR-10 and ANPEO-10 are used as the composite emulsifiers. The polymerization is initiated by potassium sulfate (KPS). The structure of latex film was characterized by Fourier transform infrared spectroscopy (FTIR). The latex films were tested by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) determinator. The particle size of the latex emulsion particle size is determined by the Zetatrac dynamic light scatter. Results show that the optimum condition of preparing the modified latex can be obtained, i.e. the amount of emulsifier is 4.0%; the mass ratio of SR-10 to ANPEO-10 is 1:1; the amount of initiator is 0.5%; the mass ratio ofVAc to VeoVa10 is 1:1; the amount of DFHMA is 5.0%. The appearance of the latex is blue and translucent with a small particle size. The conversion rate is more than 98%. Compared with the conventional latex, the hydrophobicity and heat resistance of the film have been improved. Moreover, the latex has good chemical stability and mechanical stability.

Preparation and Characterization of Self-crosslinked Acrylate Emulsified with Environmentally Friendly Surfactants

The self-crosslinking polyacrylate latex was prepared via the semi-continuous seed emulsion polymerization technology that methyl methacrylate(MMA) and butyl acrylate (BA)were used as the main monomers and hexafluorobutyl methacrylate (HFMA) and monobutylitaconate (MBI) were used as the modified monomers and glycidyl methacrylate (GMA) was used as the crosslinked monomer which were emulsified with the environmentally friendly mixed surfactant of the isomeric triethylene (9) ether (E-1309) and the lauryl polyoxyethylene ether sulfosuccinate disodium salt (MES-30). The resultant latex and its film is characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), laser particle sizer, contact angle determinator. The comparison of thermal stability between the resultant latex and conventional latex is carried out via the thermogravimetric analyzer (TGA). Factors, which have an influence on the properties of the resultant latex and the emulsion polymerization, are studied in detail. Results indicate that the thermal decomposition temperature of the latex film was increased from 336.9 °C to 370.1 °C The contact angle of the latex film is 82.9 ° owing to the introduction of GMA and MBI.

Grafted polymeric organogel using low molecular weight gelator as an effective medium for expulsion and purification of cationic dyes and organic pollutants from contaminated surface water

An increase in water pollution is a major concern for the safety of living organisms. The present work revolves around synthesizing an organogel capable of absorbing contaminated pollutants like solvents and removing cationic dyes from water surfaces. The organogel prepared using a LMWG (low molecular weight gelator) was characterized using FT-IR, SEM, NMR, TGA, and XRD spectra. Water contact angle determination was also carried out to observe the hydrophobicity. Swelling kinetics, adsorption isotherm, and intra-particle diffusion model are reported after the respective absorption and adsorption study by the gel. The highest swelling was observed in Acetic acid with swelling of 10 times its original weight. Adsorption of dyes exhibited the highest removal efficiency of 99.35% within 60 min. The organogel holds the capability to reuse dye solutions for up to 10 cycles while also holding the capacity to remove from a binary mixture of dyes. The prepared organogel serves as a potential adsorbent for environmental remediation with the potential of maximum swelling and selectivity for cationic dyes.