Friction Dynamics of Human Skin Treated using Polymer Aqueous Solutions.

Herein, we evaluated friction dynamics of human skin treated with polyacrylic acid aqueous solutions or gel creams using a sinusoidal motion friction evaluation system to demonstrate the effect of treatment with polymer aqueous solutions on human skin. A polymer aqueous solution or gel cream was applied to the inner forearms of 10 subjects to evaluate temporal changes in friction force under sinusoidal motion. Water content, skin viscoelasticity, and transepidermal water loss were also simultaneously measured to determine the effects on skin conditions.

Friction Dynamics of Straight, Curly, and Wavy Hair.

Hair shape affects the frictional properties and tactile sensation of hair. In this study, we evaluated the friction associated with the rubbing of straight, curly, or wavy hair by a contact probe equipped in a sinusoidal motion friction evaluation system. This system provides dynamic information such as the velocity dependence and hysteresis of the frictional force.

Friction Dynamics of Human Skin Treated with Oil under Nonlinear Motion.

Moisturization causes physiological changes that improve the barrier function of human skin and mechanical changes, including skin friction characteristics. This study evaluated petrolatum- or silicone oil-treated human skin to determine the effect of moisturizing on the friction dynamics. The friction force on the human skin was measured using a contact probe with a sinusoidal motion.

Mechanical Properties and Friction Dynamics of Organogels Solidified with Rice Paraffin.

Raw materials suitable for a sustainable society have attracted interest in the cosmetics industry. We focused on rice bran as a sustainable material and evaluated the gelation behavior of paraffin extracted from rice bran (rice paraffin) against liquid paraffin, squalane, jojoba oil, and silicone oil. In addition, the frictional properties of the prepared organogel on an artificial skin surface were evaluated using a sinusoidal motion friction evaluation system.

Friction Dynamics of Organogels on Artificial Skin Surfaces.

Organogels are attractive formulations in cosmetics, food, and pharmaceuticals. They exhibit characteristic frictional and mechanical responses during the collapse of a mesostructure. In this study, the friction dynamics of organogels composed of five different waxes (paraffin wax, microcrystalline wax, ceresin, candelilla wax, and carnauba wax) and liquid paraffin were evaluated using a sinusoidal motion friction evaluation system.

Friction Dynamics of Foaming Body Cleansers under Sinusoidal Motion.

The friction characteristics of foaming body cleansers determine skin physical irritation, as well as the usability of the products. In this study, the friction of foam formed by a commercial body cleanser was evaluated using a sinusoidal-motion friction evaluation system. The friction profile of the foam was a hydrodynamic stable pattern, where the friction force increased with increasing velocity.

Antimicrobial Activity of Polysorbate 80-iodine Complex: Polysorbate 80 Firmly Retains Iodine.

Considering that iodine is highly volatile and has low solubility in water, it is utilized as an antiseptic in its complex form (iodophor) with a carrier material. Herein, we prepared the polysorbate 80-iodine complex and investigated its properties. In the presence of 0%, 0.

Characterization of Powder Cosmetics Based on Friction Dynamics.

Frictional properties are one of the most important physical factors in the design of powder cosmetics. In this study, 21 powder cosmetics were applied to artificial skin, and their friction characteristics were evaluated using a sinusoidal motion friction evaluation system. Three friction profiles were observed that depended on the sliding velocity.

Characterization of Cosmetic Dispersions Based on Friction Dynamics.

Frictional properties are one of the most important physical factors in the design of cosmetic dispersions in which solid particles are dispersed in a liquid. The effects of ingredients and formulations on frictional properties have been previously reported. In this study, the frictional properties of 33 cosmetic dispersions were evaluated using a sinusoidal motion friction evaluation system when applied on an artificial skin.

Friction Dynamics of Foams under Nonlinear Motion.

Foams are viscoelastic soft materials with complex mechanical properties. Here, we evaluated the friction dynamics of foams between acrylic plates using a sinusoidal motion friction evaluation system and we found some interesting characteristics under accelerated conditions. On a typical solid surface, a symmetrical friction profile, in which static and kinetic frictions are observed, is obtained under reciprocating nonlinear motion.

Optical Properties of Pickering Emulsions and Foams.

A significant number of studies have been conducted on particle adhesion phenomena as pertaining to the oil-water interface of droplets and the air-liquid interface of bubbles, known as Pickering emulsions and Pickering foams, respectively. However, few of the literature reports have discussed the optical properties of these materials. In this study, the optical properties of Pickering particles were calculated by using an electromagnetic field analysis via a finite element method, and their optical responses are discussed.

Friction dynamics of moisturized human skin under non-linear motion.

Objective: Evaluating friction in human skin is important to assess its condition and the effects of skincare cosmetics. In this study, we evaluated the friction dynamics of moisturized skin to show the effects of moisturization on its mechanical properties.

Methods: Friction force was evaluated using a sinusoidal motion friction evaluation system.

Friction Dynamics of Wood Coated with Vegetable Oil.

Surface treatment of wood surface is an effective method to improve the physical properties. The friction dynamics of wood coated with vegetable oil were evaluated and compared to wood treated with polyurethane and untreated wood. The kinetic friction coefficient, µ , was 0.

The Selective Antibacterial Activity of the Mixed Systems Containing Myristic Acid against Staph ylococci.

Fatty acids and their derivatives are interesting cosmetic ingredients because they show the selective antibacterial activity against Staphylococcus aureus (S. aureus). However, the antibacterial activity in mixed systems containing several active ingredients is unclear because previous studies focused antibacterial systems containing one kind of fatty acid.

Nonlinear Friction Dynamics of Oil-in-Water and Water-in-Oil Emulsions on Hydrogel Surfaces.

In this study, the friction properties of emulsions in an oral environment were investigated to understand the food-texture recognition mechanisms occurring on biological surfaces. Numerous publications have suggested that the friction phenomena depend on friction conditions, such as the surface characteristics, as well as the shape and movement of contact probes. Traditional friction evaluation systems are unsuitable for mimicking the oral environment.

Antibacterial Activity of the Mixed Systems Containing 1,2-Dodecanediol against Staphylococcus aureus and Staphylococcus epidermidis.

1,2-Alkanediols are characteristic cosmetic ingredients because these moisturizers exhibit the antibacterial activity against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis).

Recognition Mechanism of the "Sara-sara Feel" of Cosmetic Powders.

The Sara-sara feel, which means "a state in which things are not damp or sticky and feel dry," is a preferred tactile sensation when people touch human skin, hair, clothing, and cosmetics. In this study, the Sara-sara feel was evaluated for silicone powder, cellulose powder, hydrophobized sericite powder, and various mixes of these powders. It was found that the highest Sara-sara feel score was achieved by the silicone powder.

Friction Dynamics of Hydrogel Substrates with a Fractal Surface: Effects of Thickness.

Interfacial phenomena on soft and wet materials, such as hydrogels, are important for modeling physical phenomena, such as friction, wetting, and adhesion on hydrophilic biosurfaces. Interfacial phenomena on soft material surfaces are not only affected by the properties of the surface but also by the geometry of the substrate. However, there are few reports on the influence of geometry and deformability on friction behavior at gel interfaces.

Nonlinear friction dynamics in the cognitive process of food textures: Thickness of polysaccharide solution.

"Thickness" is one of the descriptors of texture in liquid and semisolid foods. In this study, friction in thickener aqueous solutions was evaluated, using a biomimetic friction evaluation system, to show the correlation between friction data and sensory thickness and the recognition mechanism of this sensation during the process of eating. This system can measure friction forces under sinusoidal movement on fractal agar gel, which mimics the morphology and physical properties of the tongue.

Friction Dynamics on Human Skin Surfaces.

This study includes an evaluation of friction on the fingers, palms, and forearms of 20 subjects using a sinusoidal motion friction evaluation system. The effects of the changing water content in the stratum corneum at each position as well as the skin elastic modulus on the friction parameters were analyzed to show the factors governing friction dynamics. We observed a significant delay time (δ) and a stick-slip phenomenon during the sinusoidal motion friction processes.

Crystal Growth Technique for Formation of Double Roughness Structures Mimicking Lotus Leaf.

Bio-inspired functional materials have received much attention for their potential to provide sustainable and advanced materials. The lotus effect has proven to be one of the most remarkable biomimetic effects since it was discovered by Barthlott. A superhydrophobic surface with the ability to bounce water droplets is the origin of the self-cleaning mechanism that keeps the surface clean by removing dust using water droplets moving with momentum.

Physical origin of a complicated tactile sensation: ' feel'.

feel is defined as a texture that is moderately moisturized; however, many people experience ' feel' when they touch a dry solid material containing little liquid. Here, feel was evaluated for 12 materials. We found that the highest score of feel was achieved by powders.

Friction Dynamics on Rough Agar Gel Surfaces.

Gels exhibit complex friction behavior. This study aims to evaluate the friction forces between two fractal agar gel substrates under sinusoidal motion to show the effect of rough surfaces on friction dynamics. In a previous study, we observed an asymmetric friction profile during reciprocating motion and an ultra-low friction state on flat agar gel surfaces.

Antibacterial Activity of 1,2-Alkanediol against Staphylococcus aureus and Staphylococcus epidermidis.

1,2-Alkanediol exhibits antibacterial activity against several bacteria and yeast. However, few studies have reported antimicrobial tests on skin microbiome. Bacterial microbiome on the skin surface include Staphylococcus aureus (S.

Evaluation of Hydrophobicity for Fatty Acids Using Reversed-phase Thin Layer Chromatography.

Hydrophobicity of ingredients is important for designing food, pharmaceuticals, and cosmetics. Here, we evaluated the hydrophobicity of fatty acids and showed the effect of the alkyl length and the unsaturation degree using reversed-phase thin layer chromatography (RP-TLC). A linear relation was obtained between the methanol concentration in a mobile phase and the R value.