Higher Water Vapor Permeability Research Articles

Ultrathin skin-conformable electrodes with high water vapor permeability and stretchability characteristics composed of single-walled carbon nanotube networks assembled on elastomeric films

Herein, we report on conductive ultrathin films (nanosheets) with the characteristics of stretchability and water vapor permeability for skin-conformable bioelectrodes. The films are fabricated by combining conductive fibrous networks of single-wall carbon nanotubes (SWCNTs) and poly(styrene-b-butadiene-b-styrene) (SBS) nanosheets (i.e., SWCNT-SBS nanosheets). An increase in the number of SWCNT coatings increases both the thicknesses and densities of the SWCNT bundles. The SBS nanosheets coated with three layers of SWCNTs (i.e., SWCNT 3rd-SBS nanosheets) show comparable sheet resistance to the SBS nanosheets coated with poly(3,4-ethylenedioxithiophene) doped with poly(4-styrenesulfonate acid) (PEDOT:PSS) containing 5 wt.% butylene glycol (i.e., PEDOT:PSS/BG5-SBS nanosheets). In addition, the SWCNT 3rd-SBS nanosheets exhibit significantly reduced elastic moduli and increased elongations at break compared to the PEDOT:PSS/BG5-SBS nanosheets. Furthermore, the calculated water vapor transmission ratio of the 210-nm-thick SBS nanosheets (268,172 g m−2 (2 h)−1) is greater than that of the filter paper (6345 g m−2 (2 h)−1). The SWCNT 3rd-SBS nanosheets attached to model skin show high tolerances to bending and artificial sweat at different pH values (i.e., the electrical resistance changes ~1.1 times). Finally, the SWCNT 3rd-SBS nanosheet is applied to detect the surface electromyogram from the forearm of a subject. This nanosheet displays a signal-to-noise ratio similar to that of the PEDOT:PSS/BG5-SBS nanosheet.

Starch/chitosan nanoparticles bionanocomposite membranes for methylene blue dye removal

This research aims to develop relatively new membranes from starch biopolymer incorporated with different concentrations (0, 5, 10, 15, 20% w/w of solid starch) of chitosan nanoparticles (CNP) that can be used for water treatment. The membranes were fabricated using the solvent casting method while the CNP was produced using the ionic gelation method. The membranes were characterized in terms of morphology, porosity, water vapor permeability (WVP), and water contact angle. The application of the membranes to treat water was demonstrated on methylene blue solution because methylene blue is a commonly used dye in many industries. It was found that the starch/10% CNP membrane was the optimum membrane for methylene blue dye treatment because the membrane exhibits a smooth surface, high WVP (1.67 × 10−10 g Pa−1 h−1 m−1), high porosity (59.92%), low water contact angle value (44.8°), and resulted in the highest percentage removal of methylene blue (94.0%) after the filtration. After filtration, the starch/10% CNP membrane was still in good condition without breakage. In conclusion, the starch/CNP membranes produced in this study are promising for sustainable and environmentally friendly water treatment, especially for water containing methylene blue dye. This research aligns with current thematic trends in bionanohybrid composite materials utilization, offering innovative solutions for addressing water pollution challenges.

Extraction and Characterization of Cellulose from Broccoli Stems as a New Biopolymer Source for Producing Carboxymethyl Cellulose Films.

The use of food and agricultural waste-derived carboxymethyl cellulose (CMC) has become of interest due to their biodegradability and cost-effectiveness. In the current research, cellulose was extracted from broccoli stems to produce carboxymethyl cellulose using a carboxymethylation reaction via chloroacetic acid (CAA) and sodium hydroxide (5-10 M). The effects of different synthesis conditions on the degree of substitution (DS) and viscosity of the synthesized CMC powder were investigated. The mechanical properties, water vapor permeability (WVP), and colour of CMC films were also evaluated. The results showed that CMC with the highest DS value (0.60) and the highest viscosity of 0.5 Pa·s could be synthesized from broccoli stems at a concentration of 7.5 M NaOH and a cellulose-to-chloroacetic acid ratio of 1 : 1.2. At CMC concentration of 4 g/100 mL with 0.8 g/100 mL of glycerol, the films had the highest tensile strength (31.91 MPa), whereas with 1.2 g/100 mL glycerol, more flexible films with elongation at break of 27.56% were produced. CMC films with the highest WVP (7.87 × 103 gm2·mmHg-1/day) were made with 6 g/100 mL of CMC and 1.8 g/100 mL of glycerol. This research proposes a new source of cellulose to produce biodegradable packaging materials to initiate a practical basis for food waste reuse.

Porous Waterborne Polyurethane Films Templated from Pickering Foams for Fabrication of Synthetic Leather.

Waterborne polyurethane (WPU) latex nanoparticles with proven interfacial activity were utilized to stabilize air-water interfaces of Pickering foams through interfacial interaction with hydrophobic fumed silica particles (SPs). The rheological properties of the Pickering foam were tailored through adjustment of their SP content, which influenced their formability and stability. A Pickering foam stabilized with WPU and SPs was used as a template to prepare a WPU-SP composite porous film. The as-prepared film had intact open-cell porous structures, which increased its water absorption and water-vapor permeability. The porous film was used as a middle layer in the preparation of synthetic leather via a four-step "drying method". Compared with commercial synthetic leather, the lab-made synthetic leather with a middle layer made of the WPU-SP composite porous film exhibited a richer porous structure, acceptable wetting on a fabric substrate, a thicker porous layer, and higher water-vapor permeability. This work provides a novel and facile approach for preparing WPU-SP Pickering foams. Furthermore, the foams have the potential to function as a sustainable material for creating a porous-structured synthetic leather made from WPU, which may be utilized as an alternative to solvent-based synthetic leather.

Effect of knitting structure and dyeing process on drying time, air and vapor permeability

Comfort is the prime need in clothing. It is affected by the properties of fibers, yarns, and fabrics. A good understanding of these factors is essential in the design and conception of functional clothes. Fabric design serves as a manufacturing tool to meet several end-use requirements. The construction specifications and design of knitted fabrics greatly influence the comfort level of the end-use garment. This study aims to investigate the effect of the knitting stitch type and the dyeing process on the clothing comfort of knitted fabrics. For this purpose, five structures were prepared by combining plain, float and tuck stitches: plain jersey, cross miss 1 × 1, single cross tuck, weft lock knit and Lacoste. Then, yellow, and black dyeing were applied. The investigated wear comfort properties were the drying time, the air permeability and the relative water vapor permeability. Tests were conducted on the finished and on domestically washed fabrics. The data obtained were statistically evaluated with Pearson correlation, paired t-test, analysis of variance analysis and the Tukey test. The results showed that tucked fabrics have the longest drying time combined with the lowest air and water vapor permeability. Black variants showed better drying behavior and higher water vapor permeability. Analysis of variance results showed that the structure has a significant effect on clothing comfort. However, the dyeing process exerts a significant influence only on the drying time and the relative water vapor permeability. The paired t-test results indicate that the domestic washing cycles significantly change the drying time and the air permeability of knitted fabrics.

Sodium alginate/polyvinyl alcohol nanofibers loaded with Shikonin for diabetic wound healing: In vivo and in vitro evaluation

Diabetic wounds are typically chronic wounds and the healing process is limited by problems such as high blood glucose levels, bacterial infections, and other issues that make wound healing difficult. Designing drug-loaded wound dressings is an effective way to promote diabetic wound healing. In this study, we developed an SA/PVA nanofiber (SPS) containing Shikonin (SK) for the treatment of diabetic wounds. The prepared nanofibers were uniform in diameter, had good hydrophilicity and high water vapor permeability, and effectively promoted gas exchange between the wound site and the outside world. The results of in vitro experiments showed that SPS was effective in antimicrobial, antioxidant, and biocompatible. In vivo tests showed that the wound healing rate of mice treated with SPS reached 85.5 %. Immunohistochemical staining results showed that SPS was involved in the diabetic wound healing process through the up-regulation of growth factors (CD31, HIF-1α) and the down-regulation of inflammatory factors (CD68). Western blotting experiments showed that SPS attenuated the inflammation through the inhibition of the IκBα/NF-κB signaling pathway. These results suggest that SPS is a promising candidate for future clinical application of chronic wound dressings.

The Influence of Traditional Substrates on the Behaviour of Lime Mortars

ABSTRACTOne of the main functions of mortars is the protection of walls in-service conditions. Mortars, however, are associated with common pathological manifestations, which not only affect substrate strength and other properties, but also the comfort and healthiness of buildings users, being responsible for a significant fraction of rehabilitation expenses. In the last few decades, there has been a growing trend towards the rehabilitation of existing buildings instead of their demolition, not only for economic and urbanistic issues, but also for ecological and sustainability reasons due to the awareness of the limitation of available natural resources. In traditional buildings, lime-based renders (coating mortars) were the most common type of wall coating. Indeed, these renders have properties, such as low mechanical strength and stiffness and high-water vapour permeability, which are compatible with traditional substrates. However, inappropriate coating solutions, such as cement-based mortars, have been used in the rehabilitation of old buildings, leading to the development of anomalies in building walls. Nevertheless, there is an increasing awareness of the need to use coatings that are mechanical-chemical, physical and geometrical compatible with traditional substrates. Mortar characteristics, whether declared by the manufacturer, designer, or established by the user, are currently determined in the laboratory, according to applicable standards. When applied on substrates, mortars have their properties altered due to interaction with them, and various substrates influence differently the same mortar, as showed by extensive work developed in the scope of the IF MORTAR project. Thus, knowledge about in-service behaviour of mortars becomes crucial. The main aim of the research presented in this paper is to assess the behaviour of lime mortars applied on traditional substrates and to discuss how substrate properties affect mortar behaviour. In this way, there is a contribution to improve the understanding required to select materials for interventions in traditional buildings, assuring compatibility between traditional and new elements, with suitable durability. To achieve the above-mentioned aim, hydraulic lime mortars and hydrated air lime mortars, produced with two sands with different particle sizes, were applied on solid ceramic bricks and limestone slabs. These substrates were chosen because they are commonly found in traditional buildings. Physical and mechanical characterisation tests were carried out on the mortars hardened in laboratory moulds and on the mortars hardened on the substrates (after being detached). The substrates used were also characterised, as well as the aggregates and binders. The test results revealed that substrates have an impact on mortars characteristics, and this influence is greater for the more porous supports, and varies depending on the type of binder and aggregate used, being directly related to mortar porosity and pore distribution. For air lime mortars, there was an increase in the range of pores from 0.05 to 10 μm and a decrease for pores above 10 μm. The opposite occurred for hydraulic lime mortars. In addition, for air lime mortars, open porosity and water absorption by capillarity increased, in contrast to what happened to hydraulic lime mortars, the open porosity and water absorption by capillarity decreased, after applied to substrates and when subjected to standard curing. Regarding the type of aggregate, for the same ratio, the use of finer aggregates resulted in more porous mortars.

Biodegradable films from the lignocellulosic residue of switchgrass

Plastics thrown out as trash are an everlasting threat to our biosphere and ecosystem. A sustainable remedy within our reach is the use of agricultural biomass. Herein, the lignocellulosic residue of switchgrass biomass, extracted using alkaline and bleaching treatments and solubilized in ZnCl2 solution followed by crosslinking with calcium ions, is used to develop biodegradable films. The films have been characterized for color, transparency, thickness, moisture, water solubility, water absorption, water vapor permeability, tensile strength, elongation, and soil biodegradation. Mathematical modeling of the water absorption and biodegradation behavior have also been studied. The films are transparent, possess high tensile strength and low water vapor permeability, and biodegrade completely within 40 days at 30% soil moisture. The tensile strength and whiteness of films increase with CaCl2 concentration, but elongation, water absorption, water solubility, water vapor permeability, and biodegradation decrease. Overall, the strong and biodegradable switchgrass residue-based films open up a new window of opportunities to design and develop reusable, recyclable, and compostable films from underutilized, inexpensive, and abundant agricultural biomass contributing to the circular bioeconomy in a friendly and sustainable manner.

“Sandwich-like” structure electrostatic spun micro/nanofiber polylactic acid-polyvinyl alcohol-polylactic acid film dressing with metformin hydrochloride and puerarin for enhanced diabetic wound healing

A diabetic wound is a typical chronic wound with a long repair process and poor healing effects. It is an effective way to promote diabetic wound healing to design electrospinning nanofiber films with drug-assisted therapy, good air permeability and, a multilayer functional structure. In this paper, a diabetic wound dressing with a “sandwich-like” structure was designed. Metformin hydrochloride, loaded in the hydrophilic PVA inner layer, could effectively promote diabetic wound healing. The drug release was slowed down by osmosis. The laminate film dressing had good mechanical properties, with tensile strength and elongation at break reaching 5.91 MPa and 90.47 %, respectively, which was close to human skin. The laminate film loaded with erythromycin and puerarin in the hydrophobic PLA outer layer had good antibacterial properties. In addition, due to the high specific surface of the electrostatic spun film, it exhibited high water vapor permeability. It facilitates the gas exchange between the wound and the outside world. The cell experiments proved that the laminate film dressing had good biocompatibility. There was no toxic side effect on cell proliferation. In the diabetic animal wound model, it was shown that the closure rate of diabetic wound repair by laminate film reached 91.11 % in the second week. Our results suggest that the “sandwich-like” nanofiber film dressing could effectively promote the healing process and meet the various requirements of diabetic wound dressing as a promising candidate for future clinical application of chronic wound dressings.

A Review of the Effect of Plasticizers on the Physical and Mechanical Properties of Alginate-Based Films.

In recent years, there has been a growing attempt to manipulate various properties of biodegradable materials to use them as alternatives to their synthetic plastic counterparts. Alginate is a polysaccharide extracted from seaweed or soil bacteria that is considered one of the most promising materials for numerous applications. However, alginate potential for various applications is relatively limited due to brittleness, poor mechanical properties, scaling-up difficulties, and high water vapor permeability (WVP). Choosing an appropriate plasticizer can alleviate the situation by providing higher flexibility, workability, processability, and in some cases, higher hydrophobicity. This review paper discusses the main results and developments regarding the effects of various plasticizers on the properties of alginate-based films during the last decades. The plasticizers used for plasticizing alginate were classified into different categories, and their behavior under different concentrations and conditions was studied. Moreover, the drawback effects of plasticizers on the mechanical properties and WVP of the films are discussed. Finally, the role of plasticizers in the improved processing of alginate and the lack of knowledge on some aspects of plasticized alginate films is clarified, and accordingly, some recommendations for more classical studies of the plasticized alginate films in the future are offered.

Lightweight pumice mortars for repair of historic buildings –Assessment of physical parameters, engineering properties and durability

The subject of the presented research was an experimental analysis of physical, engineering and durability parameters of lightweight mortars intended for the repair of historical buildings. Compatibility criteria, the requirements of technical standards and guidelines, and last but not least, previously published research results dealing with the development of mortars for repair delicate historic structures were taken into account in the design of mortar composition. Crushed pumice of a similar grain size was used to lighten the reference lime-based mortar and natural hydraulic lime mortar with quartz filler. Replacement of quartz sand with pumice was 25, 50, 75 and 100% by volume. The use of pumice allowed the fundamental physical, mechanical, hygric, thermal and durability parameters of the lightweight mortars to be such that they met the standard requirements for repair mortars and the heritage conservation requirements for compatibility with the original materials of historic masonry. The main finding was the fact that by replacing sand with pumice, a significant increase in the porosity of the mortars was achieved, while maintaining sufficient mechanical strength due to the pozzolanic reaction of the pumice. Mortars based on natural hydraulic lime have become more resistant to frost and salt crystallization. The advantage of the developed mortars was their low thermal conductivity and high water vapor permeability, which made them suitable for use on damp masonry, which is a substantial scientific contribution of the manuscript.

Viscose nonwoven fabric with copper and its multifunctional properties

The antimicrobial functionalization of textile structures with copper and its compounds carried out by various methods increased significantly during the SARS-CoV-2 pandemic. So far, in order to obtain antiviral properties the magnetron technique using copper was applied mainly to flat textile structures; polypropylene, polyester and cotton nonwovens, and polyester and cotton woven fabrics. In this study, magnetron sputtering with copper was applied to modify the spatial viscose needle-punched nonwoven fabric. We found that the spatial nonwoven structure made of regenerated cellulose fibers and one-side sputtered with copper has strong antimicrobial activity against Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae. In the case of herpes simplex virus type 1 (HSV-1) McKrae strain, vaccinia virus (VACV) WR strain, influenza A virus H1N1 (IFV) and mouse coronavirus (MHV) JHV strain used in the study, Cu modified nonwoven fabric has only weak activity against herpes simplex virus type 1 (HSV-1). It also has no significant toxicity compared to the control medium and pristine nonwoven fabric. The modified nonwoven fabric is characterized also by hydrophobic properties, high electrical conductivity, good air and water vapor permeability, and meets the requirements of breathing resistance for all protection classes (FFP1, FFP2 and FFP3) specified in the EN 149-2001 standard.

Reusable and Porous Skin Patches with Thermopneumatic Adhesion Control Capability and High Water Vapor Permeability.

We present a reusable and porous skin patch (RPS patch) capable of controlling adhesion force with a thermal-pneumatic method for repetitive use as well as improving moisture permeability for long-term use without skin troubles. Previous skin patches cause skin troubles due to high adhesion force (∼30 kPa) and low moisture permeability (∼382 g/m2/day), hindering them from repeatable and long-term use. We control the skin adhesion force of the RPS patch using thermopneumatic pressure generated by an embedded heater on multiple chamber arrays. The RPS patch controls the adhesion force ranging from 8 to 29 kPa on both dry and wet skin while keeping the stable adhesion force for 48 h. It shows repeatable adhesion up to 100 times, and the adhesion force is restored after the RPS patch is washed with water, thus enabling repetitive skin adhesion. We improve the moisture permeability of the RPS patch to 733 g/m2/day while maintaining the adhesion force by making the RPS patch with porous materials. The RPS patch shows no skin troubles for 7 days of attachment, thereby being available for long-term skin attachment. The RPS patch, having adhesion control capability and high moisture permeability, shows potential for use in daily life in biomedical applications, including wearable sensors, medical adhesives, and rehabilitation robots.

Active Cellulose Acetate/Chitosan Composite Films Prepared Using Solution Blow Spinning: Structure and Electrokinetic Properties.

Cellulose acetate (CA), a very promising derivative of cellulose, has come into the focus of research due to its highly desired good film-forming ability for food packaging applications. Frequently, this derivative is used in combination with other compounds (polymers, nanoparticles) in order to obtain active materials. Here, we report the preparation of thin films made of cellulose acetate loaded with chitosan (CS) using the solution blow spinning (SBS) method. Films are prepared by SBS processing of the polymers mixture solution, considering the following variables: (i) the concentration of cellulose acetate and chitosan in the solution and (ii) the solvent system consisting of acetic or formic acid. The prepared materials are characterized in terms of physical properties, roughness (optical profilometer), porosity, wettability (contact angle measurements), chemical structure (Fourier transform infrared spectrometry), and electrokinetic properties (zeta potential). SBS enables the preparation of CA/CS films with high water vapor permeability, high porosity, and also higher water contact angle compared with pure CA films. The electrokinetic properties of composites are influenced by the inclusion of chitosan, which causes a shift of the isoelectric point (IEP) towards higher pH values, but the magnitude of the shift is not in correlation with chitosan concentration. Adsorption kinetic studies using bovine serum albumin (BSA) as a model protein reveal that chitosan modified cellulose acetate films manifest low affinity towards proteins that suggests prevention of biofilm formation on its surface.

Developing a pachyman/polyvinyl alcohol-polylactic acid bilayer film as multifunctional packaging and its application in cherry tomato preservation

Polyvinyl alcohol (PVA) is a widely used biodegradable material, but its high solubility and water vapor permeability limit its applications in food packaging. To address this issue, bilayer films were developed based on the combination of blending and coating techniques in the study, which consisted of an inner pachyman (PM)/PVA blend layer and an outer polylactic acid (PLA) layer. Blending PVA with PM reduced the solubility and oxygen permeability of the film, and the blend matrix showed rapid self-healing capabilities. Loading of a thin PLA shell onto the PM/PVA layer improved the water resistance, tensile strength, stiffness and water vapor barrier of the developed bilayer films. The best overall performance of the bilayer film was achieved using 40 g/L PLA as the film-forming solution. Infrared spectroscopic and microscopic structure analysis revealed weak interfacial interaction of the bilayer film. Furthermore, this bilayer film showed a better preservation effect on cherry tomatoes compared with PVA, polyethylene, and PM/PVA films. The physicochemical quality of fruits could be effectively preserved for at least 10 days under ambient environment. It is anticipated that the bilayer film developed here serves as a promising candidate for food packaging materials to extend the shelf life.

Characterization and functional properties of novel nanocomposite sericin-based films incorporated with sericin nanoparticles

Sericin is an interesting protein that can be formed into sericin films for biomedical and food applications. Moreover, sericin can be prepared as sericin nanoparticles (SNs) and incorporated to enhance the film barrier properties. The SNs had a size of 407 nm, as verified by dynamic light scattering. To improve the mechanical properties of sericin films, pectin was added at different ratios of sericin:pectin (w:w) (3:0, 3:1, 3:2, and 3:3). Additionally, various amounts of SNs (0, 5, and 10%) were incorporated to form nanocomposite sericin-based films. The addition of pectin and SNs led to lower solubility and higher water vapor permeability than sericin film alone. The Fourier-transform infrared results showed that the interaction between sericin and pectin molecules increased the tensile strength of the films. Furthermore, the differential scanning calorimetry results indicated that adding pectin to sericin films increased the melting temperature, resulting in improved thermal stability of the composite films. However, higher pectin content reduced the total phenolic content and antioxidant activity. Nonetheless, SNs incorporation helped increase the antioxidant activity of composite films. Thus, the nanocomposite sericin-based films could be an alternative for food packaging materials or biomedical applications.

Reinforced anticorrosive composite coating with mesh-brick structures and excellent air permeability on concrete

The commonly used resin coatings have excellent anti-corrosion properties, but cannot meet demanding performance requirements in marine environment, such as high mechanical stability and water vapor permeability. Water vapor permeability is important for concrete coating, which will discharge the residual water in the process of cement hydration. In this work, regulated poly(methyl methacrylate) (PMMA) porous and reticulated membrane (“mesh”) and two-dimensional modified zirconium phosphate (S–ZrP, “brick”) were used to form a novel “mesh-brick” structure, constructing organic-inorganic coating (S–ZrP/PMMA coating). Then, the microscopic structure of composite coatings was detailed studied, and the performance were characterized by the capillary water absorption, rapid chloride migration, abrasion resistance, and water vapor permeability (WVP) test. The results show that the coating with “mesh-brick” structures can significantly improve the hydrophobicity, impermeability, and chloride ion penetration resistance of the concrete mortar. The effect of S–ZrP concentration on the properties of composite coatings was studied, with the best impermeability performance at a concentration of S–ZrP of about 9 wt%. Benefit from the “mesh-brick” structures, the abrasion resistance of the coating has been improved, the contact angle of S–ZrP/PMMA coating did not decrease significantly, showing better stability, which reached 123.8° ± 3° even after rubbing 1000 cm. And it also greatly improved the mortar's WVP, keeping the cement-based materials air permeable. It is promising to provide long-lasting and stable protection for concrete.

Polymer-Based Wound Dressings Loaded with Ginsenoside Rg3.

The skin, the largest organ in the human body, mainly plays a protective role. Once damaged, it can lead to acute or chronic wounds. Wound healing involves a series of complex physiological processes that require ideal wound dressings to promote it. The current wound dressings have characteristics such as high porosity and moderate water vapor permeability, but they are limited in antibacterial properties and cannot protect wounds from microbial infections, which can delay wound healing. In addition, several dressings contain antibiotics, which may have bad impacts on patients. Natural active substances have good biocompatibility; for example, ginsenoside Rg3 has anti-inflammatory, antibacterial, antioxidant, and other biological activities, which can effectively promote wound healing. Some researchers have developed various polymer wound dressings loaded with ginsenoside Rg3 that have good biocompatibility and can effectively promote wound healing and reduce scar formation. This article will focus on the application and mechanism of ginsenoside Rg3-loaded dressings in wounds.

Novel silicone elastomer contact lenses designed for simultaneous viewing of distance and near eye displays

SignificanceAs technology advances, there is a need for a safe and well-fitting contact lens that can be utilized to carry embedded components without concerns of decreasing oxygen permeability to the eye. PurposeThe purpose of this study was to assess fitting characteristics, vision and performance of a novel ultra-high Dk silicone elastomer contact lens having a fully encapsulated two-state polarizing filter and a high-powered central lenslet that allows viewing at distance and viewing of a near eye display, while managing the concomitant high water vapor permeability of the material. Methods15 participants were fit with the silicone elastomer study lenses. Biomicroscopy was conducted before and after lens wear. Visual acuity with manifest refraction and visual acuity with an over-refraction while wearing the plano-powered study lenses were measured. Participants wore spectacles with micro-displays at the focal length of the lenslet on each eye. Lens fit was assessed including ease of lens removal. Subjective assessments of viewing the micro-displays were completed on a 1(unable) to 10(immediate/profound/stable) scale. ResultsBiomicroscopy revealed no eyes had moderate or severe corneal staining after study lens wear. Mean (±standard deviation) LogMAR acuity for all eyes was −0.13(0.08) with best corrected refraction and −0.03(0.06) with the study lenses and over-refraction. Mean spherical equivalent of the manifest refraction for both eyes was −3.12 D and was −2.75 D over the plano study lenses. Subjective assessments revealed a mean score of 7.67(1.91) for ease of obtaining fusion; 8.47(1.30) for ease of observing three-dimensional vision, and 8.27(1.49) for stability of the fused binocular display vision. ConclusionThe silicone elastomer study lenses with a two-state polarizing filter and central lenslet allow for vision at distance and on spectacle mounted micro-displays.

Investigation of the Usage Characteristics of Environmentally Friendly Water-Repellent Chemicals on Cotton Fabrics

Fabrics with water-repellent properties are widely valued in the textile industry. It is known that fluorocarbon compounds, which are widely used for this purpose, are harmful to the environment. Therefore, within the scope of this study, a water-repellent chemical that does not contain fluorocarbon compounds was used to treat 100% cotton fabrics and compared with fluorocarbon compounds. The results show that the environmentally friendly chemical is at least as effective as the fluorocarbon compounds. According to the spray test, water repellency at ISO 5 level was obtained. In addition, the fabrics’ usage properties were assessed and high water vapour permeability, air permeability and low bending stiffness (280 mg cm) were obtained. This has yielded important results in terms of sustainability and the potential for eliminating the use of fluorocarbons for this application.