Bioactive nanocomposites of bacterial cellulose and natural hydrocolloids

2014 ◽  
Vol 2 (40) ◽  
pp. 7034-7044 ◽  
Author(s):  
Marco Aurelio Woehl ◽  
Lucy Ono ◽  
Izabel Cristina Riegel Vidotti ◽  
Fernando Wypych ◽  
Wido Herwig Schreiner ◽  
...  
Keyword(s):  
Free Energy ◽  
Cell Growth ◽  
Bacterial Cellulose ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Growth Substrates

Bacterial cellulose–natural hydrocolloid bionanocomposites were developed as cell growth substrates. The surface free energy of the composites is related to fibroblast viability. Surface properties of the bionanocomposites can be adjusted purely by changing the component proportions.

scholarly journals THE EFFECT OF NON-POLYMERIC COMPONENTS OF A RUBBER MIXTURE ON SURFACE PROPERTIES OF ELASTOMER COMPOSITIONS

2018 ◽  
Vol 13 (5) ◽  
pp. 67-72 ◽  
Author(s):  
A. D. Tarasenko ◽  
O. A. Dulina ◽  
A. M. Bukanov
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Quantitative Characteristic ◽  
Solubility Limit ◽  
Solution Polymerization ◽  
Rubber Mixture ◽  
Rubber Compounds ◽  
Butadiene Styrene

The effect of non-polymeric components of a rubber mixture on the surface properties of butadienestyrene rubber obtained by solution polymerization was studied in the article. As non-polymeric components, ingredients widely used in the practice of the rubber industry were introduced into the rubber: fillers, surfactants of various types, and also sulfur - as a vulcanization agent. The surface free energy of the samples, a quantitative characteristic of the surface properties, was determined using the Owens-Wendt-Rabel-Kaelble method. It has been found that the surface properties of elastomeric compositions depend significantly on the solubility of the ingredients of the rubber composition and their adsorption properties. It has been shown that the most significant influence on the surface energy of butadiene-styrene rubber is exerted by the filler, on the surface of which rubber adsorption does not occur. The effect of surfactants on the surface energy of rubber compounds is different and depends on the nature of the surfactant. A partially soluble component - sulfur - in small quantities does not affect the surface energy of rubber samples. However, if it is present in the system in quantities greater than the solubility limit, it significantly reduces the surface free energy of the samples.

scholarly journals Surface characterization, hemo- and cytocompatibility of segmented poly(dimethylsiloxane)-based polyurethanes

2014 ◽  
Vol 68 (6) ◽  
pp. 731-741 ◽  
Author(s):  
Marija Pergal ◽  
Jelena Nestorov ◽  
Gordana Tovilovic-Kovacevic ◽  
Petar Jovancic ◽  
Lato Pezo ◽  
...  
Keyword(s):  
Free Energy ◽  
Endothelial Cell ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Surface Characterization ◽  
Cell Attachment ◽  
Microphase Separation ◽  
Biomedical Application ◽  
Blood Protein ◽  
Endothelial Cell Attachment

Segmented polyurethanes based on poly(dimethylsiloxane), currently used for biomedical applications, have sub-optimal biocompatibility which reduces their efficacy. Improving the endothelial cell attachment and blood-contacting properties of PDMS-based copolymers would substantially improve their clinical applications. We have studied the surface properties and in vitro biocompatibility of two series of segmented poly(urethane-dimethylsiloxane)s (SPU-PDMS) based on hydroxypropyl- and hydroxyethoxypropyl- terminated PDMS with potential applications in blood-contacting medical devices. SPU-PDMS copolymers were characterized by contact angle measurements, surface free energy determination (calculated using the van Oss-Chaudhury-Good and Owens-Wendt methods), and atomic force microscopy. The biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact assay, before and after pre-treatment of copolymers with multicomponent protein mixture, as well as by a competitive blood-protein adsorption assay. The obtained results suggested good blood compatibility of synthesized copolymers. All copolymers exhibited good resistance to fibrinogen adsorption and all favored albumin adsorption. Copolymers based on hydroxyethoxypropyl-PDMS had lower hydrophobicity, higher surface free energy, and better microphase separation in comparison with hydroxypropyl-PDMS-based copolymers, which promoted better endothelial cell attachment and growth on the surface of these polymers as compared to hydroxypropyl-PDMS-based copolymers. The results showed that SPU-PDMS copolymers display good surface properties, depending on the type of soft PDMS segments, which can be tailored for biomedical application requirements such as biomedical devices for short- and long-term uses.

Effect of the paper surface properties on the ink transfer parameters in offset printing

2019 ◽  
Vol 34 (4) ◽  
pp. 540-549 ◽  
Author(s):  
Tomislav Cigula ◽  
Tamara Tomašegović ◽  
Tomislav Hudika
Keyword(s):  
Free Energy ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Correlation Coefficients ◽  
Offset Printing ◽  
Qualitative Properties ◽  
Variable Surface ◽  
Ink Transfer ◽  
Paper Classification

Abstract Paper has a crucial impact on the qualitative properties of printed product as properties of the paper’s surface directly impact the ink transfer, consequently, basic optical properties of the print. Although same ISO paper type, papers possess variable surface properties leading to different influence on the ink transfer. The aim of this research was to analyse influence of the surface properties of the paper, including surface free energy, smoothness and gloss of some standard papers used in lithography on the ink transfer while matching the colorimetric values defined by ISO 12647-2:2013. Determination of amount of the ink transfer, optical density, mottling and colour difference of prints were performed to evaluate paper-ink interactions. Results have shown that produced prints differ in the investigated properties. Furthermore, there are significant correlations between the surface free energy of the paper and paper smoothness and the ink transfer. In addition, amount of ink used to produce a standardized print varies for different paper types (even in the same ISO paper classification), meaning difference in ink costs. This research proved the high influence of paper’s certain parameters on the ink transfer by strong correlation coefficients. This enables better process control and optimization of the printing.

Synthesis and Surface Properties of Low Surface Free Energy Silane-Functional Polybenzoxazine Films

Langmuir ◽  
2012 ◽  
Vol 29 (1) ◽  
pp. 411-416 ◽  
Author(s):  
Juan Liu ◽  
Xin Lu ◽  
Zhong Xin ◽  
Changlu Zhou
Keyword(s):  
Free Energy ◽  
Surface Properties ◽  
Surface Free Energy

Measurement of the surface free energy of calcium-montmorillonite

Clay Minerals ◽  
1986 ◽  
Vol 21 (5) ◽  
pp. 899-907 ◽  
Author(s):  
P. Chassin ◽  
C. Jounay ◽  
H. Quiquampoix
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Water Content ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Surface Characteristics ◽  
Water Molecules ◽  
Solid Water

AbstractThe surface free energy of Ca-montmorillonite has been determined from measurement of the contact angle of water on an oriented deposit immersed in n-alkanes; the oriented deposits were equilibrated at different relative humidities. These experiments provided the polar, γSP, and dispersive, γSD, components of the surface free energy γs. The results indicate that: (1) γs is mainly due to dispersive forces (γSD ≃ 145 mJ.m−2) and, to a lesser degree, polar forces (γSP ≃ 35 mJ.m−2). (2) The value of the apparent surface free energy of the clay, γα, tends towards that measured for water when the solid water content exceeds 50 wt%. (3) The sorption of water molecules substantially modifies the surface free energy of the solid; γs decreases from 180 mJ.m−2 to 60 mJ.m−2 when the water content increases from 0 to 50%. These results agree with other observations made on solids whose surface characteristics are similar to montmorillonite, i.e. micas, silicates and glasses. In addition, variations of γs with water content can be related to the hydration processes of smectites. Finally, these results show that the silicate no longer influences the surface properties when the montmorillonite water content exceeds 60%.

The Effects of Surface Modifications on Tin-Doped Indium Oxide Films: Optoelectrical, Wettability and XPS Investigations

2008 ◽  
Vol 373-374 ◽  
pp. 718-721
Author(s):  
Zhi You Zhong ◽  
Feng Lou Sun
Keyword(s):  
Free Energy ◽  
Sheet Resistance ◽  
Surface Properties ◽  
Surface Free Energy ◽  
Indium Oxide ◽  
Photoelectron Spectroscopy ◽  
Surface Modifications ◽  
Optical Transmittance ◽  
Contact Angles ◽  
Oxygen Plasma Treatment

Surface modifications were performed on the tin-doped indium oxide (ITO) substrates for optoelectronic devices, using the different processing techniques. The effects of modification methods on the surface properties of ITO substrates were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ultraviolet-visible (UV-vis) spectrophotometer, standard goniometry and four-probe meter, respectively. The surface free energy as the sum of the dispersion and polar components was evaluated from the measured contact angles using the Owens-Wendt approach. Experimental results demonstrate that except the optical transmittance of the ITO, the surface properties including the stoichiometry, morphology, wettability and sheet resistance of the ITO substrates strongly depend on the modification methods. Compared with the other treatments, the oxygen plasma treatment increases the oxygen concentration and decreases the carbon concentration, reduces the surface roughness and the sheet resistance, and enhances the surface free energy and the polarity, and thereby more effectively improves the surface properties of ITO substrates.

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