The Experts below are selected from a list of 98346 Experts worldwide ranked by ideXlab platform
Pedro Luiz Manique Barreto - One of the best experts on this subject based on the ideXlab platform.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
Jefferson Rotta - One of the best experts on this subject based on the ideXlab platform.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
Chencheng Sun - One of the best experts on this subject based on the ideXlab platform.
-
Surface Free Energy of non stick coatings deposited using closed field unbalanced magnetron sputter ion plating
Applied Surface Science, 2007Co-Authors: Chencheng Sun, Shihchin Lee, Shyuebin Dai, Sheinlong Tien, Chungchih Chang, Yawshyan FuAbstract:Abstract Semiconductor IC packaging molding dies require wear resistance, corrosion resistance and non-sticking (with a low Surface Free Energy). The molding releasing capability and performance are directly associated with the Surface Free Energy between the coating and product material. The serious sticking problem reduces productivity and reliability. Depositing TiN, TiMoS, ZrN, CrC, CrN, NiCr, NiCrN, CrTiAlN and CrNiTiAlN coatings using closed field unbalanced magnetron sputter ion plating, and characterizing their Surface Free Energy are the main object in developing a non-stick coating system for semiconductor IC molding tools. The contact angle of water, diiodomethane and ethylene glycol on the coated Surfaces were measured at temperature in 20 °C using a Dataphysics OCA-20 contact angle analyzer. The Surface Free Energy of the coatings and their components (dispersion and polar) were calculated using the Owens–Wendt geometric mean approach. The Surface roughness was investigated by atomic force microscopy (AFM). The adhesion force of these coatings was measured using direct tensile pull-off test apparatus. The experimental results showed that NiCrN, CrN and NiCrTiAlN coatings outperformed TiN, ZrN, NiCr, CiTiAlN, CrC and TiMoS coatings in terms of non-sticking, and thus have the potential as working layers for injection molding industrial equipment, especially in semiconductor IC packaging molding applications.
-
Surface Free Energy of alloy nitride coatings deposited using closed field unbalanced magnetron sputter ion plating
Materials Transactions, 2006Co-Authors: Chencheng Sun, Shihchin Lee, Wenchi Hwang, J S Hwang, Itseng TangAbstract:The sticking of product material to injection molding tools is a serious problem, which reduces productivity and reliability. Depositing alloy nitride coatings (TiN, ZrN, CrN, and TiAlCrN) using closed field unbalanced magnetron sputter ion plating and electrodeposition of chromium, and characterizing their Surface Free energies in the temperature range 20–120 � C have led to the development of a non-sticking (with a low Surface Free Energy) coating system for semiconductor IC packaging molding dies. The contact angles of water, diiodomethane and ethylene glycol on the coated Surfaces were measured at temperatures in the range 20–120 � C using a Dataphysics OCA-20 contact angle analyzer. The Surface Free Energy of the coatings and their components (dispersion and polar) were calculated using the Owens-Wendt geometric mean approach. The Surface roughness of these coatings were investigated by atomic force microscopy (AFM). The adhesion force of these coatings were measured using direct tensile pull-off test apparatus. The experimental results revealed that TiAlCrN, CrN and ZrN coatings outperformed Hard-Cr and TiN coatings in terms of anti-adhesion, and thus have the potential as working layers for injection molding industrial equipment, especially in semiconductor IC packaging molding applications. [doi:10.2320/matertrans.47.2533]
-
Surface Free Energy of crnx films deposited using closed field unbalanced magnetron sputtering
Applied Surface Science, 2006Co-Authors: Chencheng Sun, Shihchin Lee, Shyuebin Dai, Yauchyr Wang, Yuhwe LeeAbstract:Abstract CrN x thin films have attracted much attention for semiconductor IC packaging molding dies and forming tools due to their excellent hardness, thermal stability and non-sticking properties (low Surface Free Energy). However, few data has been published on the Surface Free Energy (SFE) of CrN x films at temperatures in the range 20–170 °C. In this study CrN x thin films with CrN, Cr(N), Cr 2 N (and mixture of these phases) were prepared using closed field unbalanced magnetron sputtering at a wide range of Cr +2 emission intensity. The contact angles of water, di-iodomethane and ethylene glycol on the coated Surfaces were measured at temperatures in the range 20–170 °C using a Dataphysics OCA-20 contact angle analyzer. The Surface Free Energy of the CrN x films and their components (e.g., dispersion, polar) were calculated using the Owens–Wendt geometric mean approach. The influences of CrN x film Surface roughness and microstructure on the Surface Free Energy were investigated by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. The experimental results showed that the lowest total SFE was obtained corresponding to CrN at temperature in 20 °C. This is lower than that of Cr(N), Cr 2 N (and mixture of these phases). The total SFE, dispersive SFE and polar SFE of CrN x films decreased with increasing Surface temperature. The film roughness has an obvious effect on the SFE and there is tendency for the SFE to increase with increasing film Surface roughness.
Emil Chibowski - One of the best experts on this subject based on the ideXlab platform.
-
Surface properties of ti 6al 4v alloy part i Surface roughness and apparent Surface Free Energy
Materials Science and Engineering: C, 2017Co-Authors: Yingdi Yan, Emil Chibowski, Aleksandra SzcześAbstract:Titanium (Ti) and its alloys are the most often used implants material in dental treatment and orthopedics. Topography and wettability of its Surface play important role in film formation, protein adhesion, following osseointegration and even duration of inserted implant. In this paper, we prepared Ti-6Al-4V alloy samples using different smoothing and polishing materials as well the air plasma treatment, on which contact angles of water, formamide and diiodomethane were measured. Then the apparent Surface Free Energy was calculated using four different approaches (CAH, LWAB, O-W and Neumann's Equation of State). From LWAB approach the components of Surface Free Energy were obtained, which shed more light on the wetting properties of samples Surface. The Surface roughness of the prepared samples was investigated with the help of optical profilometer and AFM. It was interesting whether the Surface roughness affects the apparent Surface Free Energy. It was found that both polar interactions the electron donor parameter of the Energy and the work of water adhesion increased with decreasing roughness of the Surfaces. Moreover, short time plasma treatment (1min) caused decrease in the Surface hydrophilic character, while longer time (10min) treatment caused significant increase in the polar interactions and the work of water adhesion. Although Ti-6Al-4V alloy has been investigated many times, to our knowledge, so far no paper has been published in which Surface roughness and changes in the Surface Free Energy of the alloy were compared in the quantitative way in such large extent. This novel approach deliver better knowledge about the Surface properties of differently smoothed and polished samples which may be helpful to facilitate cell adhesion, proliferation and mineralization. Therefore the results obtained present also potentially practical meaning.
-
Surface Free Energy of a solid from contact angle hysteresis.
Advances in Colloid and Interface Science, 2003Co-Authors: Emil ChibowskiAbstract:Nature of contact angle hysteresis is discussed basing on the literature data (Colloids Surf. A 189 (2001) 265) of dynamic advancing and receding contact angles of n-alkanes and n-alcohols on a very smooth Surface of 1,1,2,-trichloro-1,2,2,-trifluoroethane (FC-732) film deposited on a silicon plate. The authors considered the liquid absorption and/or retention (swelling) processes responsible for the observed hysteresis. In this paper hysteresis is considered to be due to the liquid film left behind the drop during retreating of its contact line. Using the contact angle hysteresis an approach is suggested for evaluation of the solid Surface Free Energy. Molecular spacing and the film structure are discussed to explain the difference in n-alkanes and n-alcohols behaviour as well as to explain the difference between dispersion Free Energy γsd and total Surface Free Energy γstot of FC-732, as determined from the advancing contact angles and the hysteresis, respectively.
-
problems of contact angle and solid Surface Free Energy determination
Advances in Colloid and Interface Science, 2002Co-Authors: Emil Chibowski, R PereacarpioAbstract:The current general problems of formulation and determination of Surface Free Energy are discussed. So far several theories and approaches have been proposed, but formulation of Surface and interfacial Free Energy, as regards its components, is still a very debatable issue. However, as long as no method for determination of real Surface Free Energy quantities is known, even relative values charged with many simplified assumptions are useful for better understanding of the wetting processes. In this paper special focus is concentrated on powdered solids for which direct measurement of the contact angles is not possible. For such solids the porous layer imbibition techniques are most frequently applied. Then, using the wicking results the contact angle is calculated from Washburn's equation. However, such a procedure leads to overestimated contact angle values in comparison to those measured directly on smooth Surfaces of the same solid, if such Surface can be obtained at all. As a consequence, the solid Surface Free Energy components calculated via such overestimated contact angles are significantly lower than those obtained from contact angles measured directly. Methodologies to avoid this problem are also described.
-
comparison of the lifshitz van der waals acid base and contact angle hysteresis approaches for determination of solid Surface Free Energy
Journal of Adhesion Science and Technology, 2002Co-Authors: Henryk Radelczuk, Lucyna Holysz, Emil ChibowskiAbstract:Total Surface Free Energy, γS TOT, for several solids (glass, PMMA, duralumin, steel and cadmium) was calculated from the Surface Free Energy components: apolar Lifshitz–van der Waals, γS LW, and acid–base electron–donor, γS -, and electron–acceptor, γS +. Using van Oss and coworkers' approach (Lifshitz–van der Waals/acid–base (LWAB) approach), the components were determined from advancing contact angles of the following probe liquids: water, glycerol, formamide, diiodomethane, ethylene glycol, 1-bromonaphthalene and dimethyl sulfoxide. Moreover, receding contact angles were also measured for the probe liquids, and then applying the contact angle hysteresis (CAH) approach very recently proposed by Chibowski, the total Surface Free Energy for these solids was calculated. Although the thus determined total Surface Free Energy for a particular solid was expected to depend on the combination of three probe liquids used (LWAB approach), as well as on the kind of the liquid used (CAH approach), surprisingly the...
-
Use of the Washburn equation for Surface Free Energy determination
Langmuir, 1992Co-Authors: Emil Chibowski, Lucyna HołyszAbstract:The thin-layer wicking technique was used to determine the solid Surface Free Energy components for thin-layer chromatography silica (Merck) by the Washburn equation. It has been found that wick-wetting is a reproducible process and the results of the wetting rates expressed as the relationship of the penetrated distances squared, x2 , are a linear function of time, t. However, in some systems an inflection appeared at a distance 3 5 x 5 5 cm, giving thus two straight-line sections with somewhat different slopes. nAlkanes, diiodomethane, water, and formamide were used as the penetrating liquids. Van Oss et al.'s approach to the Surface Free Energy was applied. Thus, apolar, ysLw, and polar electron donor, ys, and electron acceptor, ys+, components were determined for both the laboratory-made glass plates with a deposited Si02 thin layer as well as commercial ones. Practically the same value of ysLw was obtained for both kinds of plates. However, the commercial plates showed higher values of the yscomponent. It is probably due to the presence of some adhesive additives. The polar ys+ component is small for both plates. It is believed that this technique and the approach to the Surface Free Energy components are very useful for testing the wetting properties of solids by liquids.
Renata Dias De Melo Castanho Amboni - One of the best experts on this subject based on the ideXlab platform.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
-
parameters of color transparency water solubility wettability and Surface Free Energy of chitosan hydroxypropylmethylcellulose hpmc films plasticized with sorbitol
Materials Science and Engineering: C, 2009Co-Authors: Jefferson Rotta, Renata Avila Ozorio, Andre Michel Kehrwald, Guilherme M O Barra, Renata Dias De Melo Castanho Amboni, Pedro Luiz Manique BarretoAbstract:Abstract This work examined the parameters of color, transparency, water solubility, wettability and Surface Free Energy of chitosan/ydroxypropylmethylcellulose (HPMC) blends plasticized with sorbitol. The solutions of chitosan and hydroxypropylmethylcellulose were mixed in different proportions (100/0; 70/30; 50/50; 30/70 and 0/100 respectively), and 20 mL was casting in Petri dishes to posterior analysis of formed films. The CIELab method was used to determine the L ⁎, a ⁎ and b ⁎ color values of the samples. The color was affected by different proportion of chitosan/hydroxypropylmethylcellulose. The higher the HPMC proportion in the films, the higher the solubility in water. Contact angle measurements showed an increment in the values of the polar Surface Free Energy and the hydrophilic character when HPMC component was increased in the blend.
