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PubMed2006

Plasma-based processes for surface wettability modification.

In this article, we describe a method to create rough features on silicon surfaces by reactive etching of a photoresist layer. The roughness and, consequently, the wettability of the surfaces can be modified by modifying the duration of plasma etching. Hydrophobic materials deposited on the rough silicon surface can be modified until a superhydrophobic behavior is obtained, whereas hydrophilic materials become more hydrophilic. The elaboration technique described herein offers an inexpensive and rapid method for the creation of tunable roughness on silicon surfaces with large areas.

Hydrophobic and Hydrophilic Interactions↗
PubMed2000

Effect of surface treatments on the wettability of vinyl polysiloxane impression materials.

STATEMENT OF PROBLEM: A number of vinyl polysiloxane (VPS) impression materials are claimed to be hydrophilic, but it has been hypothesized that the degree of hydrophilicity may be altered by the exposure to saliva, disinfecting agents, and surfactants. PURPOSE: This study compared the effects of 6 treatment regimes on the hydrophilicity of 3 VPS materials. MATERIAL AND METHODS: Three VPS materials (Dimension Garant L, Hydroflex, Imprint II, referred to as G, H, and I, respectively) were each treated with: (1) nothing (control), (2) saliva, (3) saliva and NaOCl, (4) saliva and 2-propanol-based disinfectant, (5) saliva, NaOCl and surfactant, and 6) saliva, 2-propanol-based disinfectant, and surfactant. Advancing contact angles (thetaA) were measured using a Cahn Dynamic contact angle analyzer and WinDCA software. Using saturated CaSO4 solutions, thetaA was determined for the 3 materials in each of the 6 conditions. For each combination of VPS and treatment, 5 determinations were made using fresh samples and fresh solution each time. Considerable contact angle hysteresis was observed. Two-way ANOVA was performed, followed by post-hoc Boneferroni-Dunn tests. RESULTS: For all outcome variables, the treatment effects were not the same for all materials (P < .001). However, for all materials, treatments that included surfactants were among the groups with the lowest thetaA values and thus had the best wettability. For example, materials G and I, as made, had high thetaA values (109.7 and 115.2 degrees, respectively), but these values reduced to approximately 90 degrees after surfactant treatment. Material H had a thetaA value of 87.1 degrees. Exposure of material H to saliva and/or a disinfectant raised this value, but a thetaA close to the original value was achieved by the use of a surfactant. CONCLUSION: Treatments affected the VPS materials in different ways but, after disinfectant treatment, the wetting of "hydrophilic" VPS materials was improved by surfactant treatment.

1-Propanol↗
PubMed2004

Assessment of spray application of Saint GERVAIS water effects on skin wettability by contact angle measurement comparison with bidistilled water.

BACKGROUND: The skin is responsible for protecting the body from physical, chemical and microbial injuries. The stratum corneum is the top layer of the epidermis and it plays a key role in helping to contain moisture. When the skin becomes damaged, its ability to perform these functions is compromised. Dry skin is a common form of skin damage. Contact angle 0 between a surface and water is a good indicator of hydrophobic or hydrophilic tendency of surfaces. OBJECTIVE: To quantify the influence of spray application of an isotonic mineral water (Saint GERVAIS water) on the hydrophobic tendency of dry skin and to compare spreading of both types of water on the skin through 0 measurement of each water drop on the skin before and after mineral spray application. MATERIALS AND METHODS: Contact angles theta between skin surface and the two types of water (bidistilled and mineral water) were measured before and after application of mineral water by a system allowing the measurement of theta in vivo and in vitro. The cutaneous hydration, the temperature and pH were also measured before and after mineral water application. RESULTS: As for the application of mineral water, the cutaneous pH significantly increased so the strong skin acidity decreased. The cutaneous temperature was modified (a decrease of 2 degrees C was noted) and the cutaneous hydration was also increased (+47AU). The hydro-phobic tendency of the dry skin tested in this study was strongly decreased after mineral water application. This parameter was illustrated by a decrease of contact angle theta value. CONCLUSION: Saint GERVAIS water application allowed a regulation of skin pH, a fresh sensation on the skin and an increase in the cutaneous hydration. Moreover, the contact angle measurement with bidistilled water illustrated the increased wettability of the skin.

Administration, Topical↗
PubMed2006

Influence of polishing of denture base resin and metal surfaces on wettability with water and saliva.

The purpose of this study was to investigate the influence of the surface roughness of denture base resin and metal on wettability with water and saliva. Solid specimens were produced using heat-curing denture base resin and Co-Cr alloy. After polymerizing or casting these materials, specimens with four different types of surface roughness were produced by a progressive polishing process using polishing papers (#240, #400, and #1,000) and cotton buffs. Surface roughness decreased significantly as the polishing process progressed (p<0.0001). Contact angle increased as surface roughness in metal specimens decreased, but decreased as surface roughness in resin specimens decreased (p<0.0001). Furthermore, differences in contact angle between tap water and saliva were larger in metal specimens (p<0.0001). These results suggested that with regard to the tissue surface of a denture base, the influence of its roughness on adhesive force differed according to the type of denture base material.

Acrylic Resins↗
PubMed2002

In vitro studies of the influence polyester materials with a different degree of surface wettability have on blood haematological parameters and coagulation and fibrinolysis system parameters.

The paper presents the studies of the influence polyester knitings with a different degree of surface wettability have on the coagulation system, fibrinolytic system and blood haematological parameters in in vitro studies. The studies of Human whole blood were performed for 5, 15, 30, 60, 90, 180 and 240 min. In view of the obtained results in has been reported that a hydrophobic surface knitting does not cause important quantitative changes in any of the selected parametes of the coagulation system and fibrinolysis system. A hydrophilic surface polyester knit causes important lengthening of aPTT value and reduced factor XII, IX and VIII activity. A hydrophilic surface polyester knitting causes a bigger decrease in leukocytes and blood platelets and a bigger increase in beta thromboglobulin in relation to the hydrophobic surface knitting. Neither hydrophobic surface knit nor hydrophilic surface knitting cause changes in the erythrocyte system.

Blood Coagulation↗
PubMed2004

Wettability of some packable resin-based composites. An in vitro study.

The purpose of this research was to measure the contact angles of some packable resin-based composites in order to determine their wettability related to the surface energy. Materials were manipulated according to the manufacturer's instructions and were inserted in a circular metallic matrix and photo cured for 40 seconds on both sides. The specimens were removed and finished with silicon carbide metallurgical finishing paper (800 gifts). Half of each specimen was covered by a layer of Bis-GMA and photo cured for 20 seconds. The specimens were then submitted to measurements in a contact angle goniometer with two different liquids and polarities in three points. The materials without Bis-GMA covering layer showed statistically significant differences related to contact angles and among the materials and liquids (p<0/05).

Bisphenol A-Glycidyl Methacrylate↗
PubMed1994

Effect of wettability of adhesive resins on bonding to dentin.

The purpose of this study was to investigate on human dentin the relationships between, on the one hand, the wettability of five adhesive compounds, characterized by different solubility parameters delta, and on the other, the thickness of the resin impregnated dentin layer (RIL) and the shear bond strength (SBS). Cut dentin surfaces were treated with conditioners of pH 1.25, 3.6 or 7.4. Shear bond strength was measured on 20 specimens each. RIL was determined by scanning electron microscope on specimens fractured perpendicularly to the bonding interface. When resins with delta 32, 30 or 39 (MJ1/2/m3/2) were used RILs were consistently 4 microns and 1 micron on dentin pretreated with the two acidic conditioners. No clearly measurable RIL was shown after application of the conditioner with pH 7.4, and when resins with delta-values of 20 and 25 were applied. For the same adhesive no difference in SBS was found, when applied on the differently conditioned dentin sites. Resins with delta > 30 produced significantly higher SBS than the two adhesives with smaller delta.

Analysis of Variance↗
PubMed1996

Influence of enamel prophylaxis on wettability of three commercially available orthophosphoric acids.

An in vitro study was performed to assess the wettability of orthophosphoric acid after different procedures for cleaning the enamel surface. Ninety noncarious third molars were randomly distributed into three groups with different enamel surface treatments: an air-powder polisher unit, prophylaxis pastes, and no enamel surface cleaning. Three commercially available orthophosphoric acids were used, and there were 10 teeth in each group. Acid viscosity values and contact-angle measurements were obtained. Each enamel surface was also examined with the scanning electron microscope. Results suggested that the surface treatment with which the best spreading of the acid solution was attained was the air-powder polisher. The least spreading of the acid was obtained with prophylaxis pastes, in which contact angles were even higher than those obtained on the untreated enamel surface. The 3M acid solution was the one that showed the best spreading onto the enamel surface.

Acid Etching, Dental↗
PubMed2002

Interaction of human skin fibroblasts with moderate wettable polyacrylonitrile--copolymer membranes.

The development of a bioartificial skin is a step toward the treatment of patients with deep burns or nonhealing skin ulcers. One possible approach is based on growing dermal cells on membranes to obtain appropriate living cellular stroma (sheets) to cover the wound. New membrane-forming copolymers were synthesized, based on acrylonitrile (AN) copolymerization with hydrophilic N-vinylpyrrolidone (NVP) monomer, in different percentage ratios, such as 5, 20, and 30% w/w, and with two other relatively high polar comonomers--namely, sodium 2-methyl-2-propene-1-sulfonic acid (NaMAS) and aminoethylmethacrylate (AeMA). All these copolymers were characterized for their bulk composition and number average molecular weight, and used to prepare ultrafiltration membranes. Water contact angles and water uptake were estimated to characterize the wettability and scanning force microscopy to visualize the morphology of the resulting polymer surface. Cytotoxicity was estimated according to the international standard regulations, and the materials were found to be nontoxic. The interaction of the membranes with human skin fibroblasts was investigated considering that these cells are among the first to colonize membranes upon implantation or with prolonged external contact. The overall cell morphology, formation of focal adhesion contacts, and cell proliferation were estimated to characterize the cell material interactions. It was found that the pure polyacrylonitrile homopolymer (PAN) membrane provides excellent conditions for seeding with fibroblasts, comparable only to a copolymer containing AeMA. In contrast, the presence of NaMAS with acidic ionic groups decreased both the attachment and proliferation of fibroblasts. Low content of NVP in the copolymer, up to about 5%, still enabled good attachment and spreading of cells, as well as subsequent proliferation of fibroblasts, but higher ratios of 20 and 30% resulted in a significant decrease of these cellular activities.

Acrylic Resins↗
PubMed1987

Competition between adsorbed fibrinogen and high-molecular-weight kininogen on solid surfaces incubated in human plasma (the Vroman effect): influence of solid surface wettability.

The influence of the surface energy on the competition between fibrinogen and high-molecular-weight kininogen has been studied with the use of a recently described wettability gradient method. One finding is that the decrease in the antifibrinogen binding on plasma incubated gradient surfaces was not associated with an increase in anti-HMWK binding at all parts of the gradient surfaces.

Adsorption↗
PubMed1992

Influence of calcium concentration on the dentin wettability by an adhesive.

Plane dentin surfaces were abraded perpendicular to the radicular axis of sound human molars. They were cleaned to reveal the tubules, and the morphological features of each surface were studied microscopically. For a first series of teeth, the Vickers microhardness of the dentin surfaces was measured and the calcium and phosphorus composition was determined by electron microprobe analysis. For a second series, the microhardness and wettability of the surface by the Scotchbond adhesive were compared. Positive correlations were found between the following parameters: degree of minerality, dentin compactness, hardness, and spreading capability of the adhesive.

Calcium↗
PubMed1994

In vitro chondrocyte collagen deposition within porous HDPE: substrate microstructure and wettability effects.

The effects of microstructure and wettability of porous high density polyethylene (HDPE) substrates on chondrocyte collagen synthesis in vitro were assayed. Three size grades of hydrophilic and hydrophobic HDPE substrates with ranges of pore volumes of 40-60%, pore sizes of 115-335 microns, and surface areas per unit volumes of 7-20 mm2/mm3 were seeded with fetal bovine chondrocytes. After 7 days of incubation, the cells within all substrates remained spherical, and contained mainly type II collagen (as verified by type I and II collagen I-ELISAs). After 21 days, the majority of cells had spread; however, the matrices still contained mainly type II collagen. The hydrophilic matrices contained significantly more type II collagen than the hydrophobic matrices at both 7 and 21 days, whereas the amount of type II collagen was not influenced by the pore attributes. A significantly higher percentage of type II collagen was also observed in all seeded porous substrates as compared with seeded polystyrene culture dishes, perhaps indicating that the three-dimensional particular nature of the HDPE matrices enhanced the maintenance of phenotypically differentiated chondrocytes and entrapment of their extracellular matrix products.

Animals↗
PubMed1976

Wettability of pharmaceutical solids: estimates of solid surface polarity.

Contact angle measurements of water and methylene iodide with various organic solids were used to estimate the surface free energy per square centimeter, gammaS, and the contributions of nonpolar and polar forces, gammaSd and gammaSp, respectively. The ratio of gammaSp to gammaS was used as an estimate of solid surface polarity, and values ranging from 0 to 42% polarity were calculated for materials of pharmaceutical interest. Surface free energies per mole were calculated to compare the influence of different substituent groups on wettability. This approach offers a convenient means to quantitate the polarity of organic pharmaceutical solid surfaces.

Chemistry, Pharmaceutical↗
PubMed1999

Wettability, Oil Recovery, and Interfacial Tension with an SDBS-Dodecane-Kaolin System.

The wettability of kaolin with SDBS (sodium dodecyl benzene sulfonate) aqueous solutions was measured by the Washburn equation expressed as contact angles. The contact angle changes for SDBS aqueous solutions on kaolin surface was studied. The interfacial tension between the SDBS solutions and n-dodecane was measured using both drop volume and spinning drop methods. Then the oil recovery of n-dodecane on the kaolin surface was tested. It was found that the minimum contact angle (the most hydrophilic condition) and the maximum oil recovery occurred near the critical micelle concentration (CMC) of SDBS while the interfacial tension between the SDBS solution and n-dodecane was far from ultra-low. Copyright 1999 Academic Press.

Journal Article↗
PubMed2000

Ultrathin SiO(x) Film Coating Effect on the Wettability Change of TiO(2) Surfaces in the Presence and Absence of UV Light Illumination.

Wettability of sol-gel TiO(2) film surfaces has been studied by following the H(2)O contact angle (straight theta) as functions of illumination time and subsequent dark storage time. Upon illumination of the TiO(2) surface (lambda(ex)>300 nm), the value of straight theta rapidly decreased to reach approximately zero (photoprocess). When the resultant superhydrophilic sample was stored in the dark, the straight theta value increased slowly with increasing storage time (dark process). Ultrathin SiO(x) films were formed on the surface of TiO(2) by repeating chemisorption of 1,3,5,7-tetramethylcyclotetrasiloxane and its photooxidation. With increasing thickness of the SiO(x) monolayer coating, the rate for the dark process significantly decreased, while that for the photoprocess also decreased. Both X-ray photoelectron spectroscopic studies and product analyses during the photoprocess clarified that photocatalytic oxidation of organic adsorbates in air causes the superhydrophilicity of the TiO(2) surfaces. Copyright 2000 Academic Press.

Journal Article↗
PubMed1995

Development and characterization of a wettable surface modified aromatic polyethersulphone using glow discharge induced HEMA-graft polymerisation.

The aromatic polyethersulphone (PES) is a well known polymer for the preparation of membranes with excellent thermal stability and chemical resistance. The disadvantage of PES-membranes is their hydrophobic character, which in contact with protein containing solutions leads to high protein adsorption and as a consequence to deterioration of membrane properties. In this report the surface modification of PES by means of glow discharge induced grafting of 2-hydroxyethyl methacrylate (HEMA) is described. Graft polymerisation creates a largely wettable layer of poly(2-hydroxyethyl methacrylate) (PHEMA) on the surface of PES. This has been shown by contact angle measurements using the Wilhelmy plate method. Chemical characterization is carried out by means of X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy/attentuated total reflection (FTIR-ATR). The influence of storage conditions on the surface properties of modified PES samples has been investigated after storage in vacuum, water, and air.

Journal Article↗
PubMed2006

Wettability of calcite and mica modified by different long-chain fatty acids (C18 acids).

The effect of long-chain fatty acid adsorption on the wetting states of calcite and mica powders is investigated. The selected long-chain fatty acids are saturated or unsaturated aliphatic acids (stearic acid and oleic acid, respectively) and naphthenic acids with saturated or unsaturated aromatic rings (18-cyclohexyloctadecanoic acid and 18-phenoloctadecanoic acid, respectively). The amount of irreversibly adsorbed acid is determined by thermogravimetric analysis. The affinity of water and n-decane for these samples before and after modification is deduced from their adsorption isotherm and microcalorimetry. Thermodynamic analysis of surface pressure and spreading tension are performed based on adsorption isotherms. The enthalpy versus coverage curve for water adsorption and its comparison to liquefaction enthalpy is shown to be a meaningful method for characterizing the wettability of a surface. The naphthenic acid with unsaturated aromatic ring deeply modifies the calcite to an oil-wet state. The mica powder was not as strongly modified as calcite by these acid molecules.

Journal Article↗