Surface Adhesion (surface + adhesion)

Distribution by Scientific Domains

Selected Abstracts

Bone Implants: (Osteoconductive and Osteoinductive Properties of Zeolite MFI Coatings on Titanium Alloys) Adv.

Biocompatible zeolite anti-corrosion coatings have potential for success as bone scaffolding materials. In this work, reported by Y. Yan and co-workers, titanium-based dental implants are covered with zeolite MFI coatings to prevent against corrosion within the dental cavity. Zeolite coatings are non-toxic, and prevent the release of toxic ions from metals into tissue. The 3D micro-topology of the zeolites also enhances cell proliferation, differentiation, and surface adhesion. [source]

Preparation and self-assembly of polyaniline nanorods and their application as electroactive actuators

Seong Hun Kim
Abstract To improve the performance of ion-exchange polymer,metal composite (IPMC) actuators, an electrical pathway material for enhancing the surface adhesion between the membrane and the metal electrodes of the IPMC was studied. As an efficient electrical pathway material, polyaniline nanorods (PANI-NRs) doped with p -toluene sulfonic acid (TSA) were synthesized with a template-free method. The factors affecting polyaniline morphology were studied with various dopant concentrations and oxidant feeding rates. Highly conductive PANI-NRs were formed when they were synthesized with ammonium persulfate at a 5.0 mL/min oxidant feeding rate and doped with 0.125M TSA. The conductivity of the PANI-NRs was 1.15 10,1 S/cm, and their diameters and lengths were 120,180 nm and 0.6,2 ,m, respectively. To apply the membrane as an actuator, perfluorosulfonated ionomer (Nafion)/PANI-NR blends were prepared by solution blending and casting. The actuating ability of the three-layered membrane consisting of Nafion/PANI-NR blends was then examined and compared with that of Nafion only. The actuating ability of the IPMC was improved when Nafion/PANI-NRs were used as electrical pathways. 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

A study of dye molecule diffusion in human hair using positron lifetime spectroscopy

M. N. Chandrashekara
Abstract The diffusion behavior of a commercial permanent liquid hair dye in human hair has been investigated using Positron Annihilation Lifetime Spectroscopy (PALS) and gravimetric sorption method. The o-Ps lifetime parameters ,3 and I3 decrease rapidly during the first 60 minutes of sorption time. This is understood in terms of dye molecules filling the free volume cavities in hair. The sorption results suggest that the dye molecule diffusion is essentially a Fickian process. In the latter part of the sorption, where positron parameters remain almost constant, mass increase might be due to surface adhesion. These two stages of sorption are well separated by the positron technique. The study shows that the free volume theory and positron technique, widely used in polymer research, may expediently be used to understand hair properties, more importantly diffusion of dye molecules. ( 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Intercellular adhesion and cell separation in plants

ABSTRACT Adhesion between plant cells is a fundamental feature of plant growth and development, and an essential part of the strategy by which growing plants achieve mechanical strength. Turgor pressure provides non-woody plant tissues with mechanical rigidity and the driving force for growth, but at the same time it generates large forces tending to separate cells. These are resisted by reinforcing zones located precisely at the points of maximum stress. In dicots the reinforcing zones are occupied by networks of specific pectic polymers. The mechanisms by which these networks cohere vary and are not fully understood. In the Poaceae their place is taken by phenolic cross-linking of arabinoxylans. Whatever the reinforcing polymers, a targeting mechanism is necessary to ensure that they become immobilized at the appropriate location, and there are secretory mutants that appear to have defects in this mechanism and hence are defective in cell adhesion. At the outer surface of most plant parts, the tendency of cells to cohere is blocked, apparently by the cuticle. Mutants with lesions in the biosynthesis of cuticular lipids show aberrant surface adhesion and other developmental abnormalities. When plant cells separate, the polymer networks that join them are locally dismantled with surgical precision. This occurs during the development of intercellular spaces; during the abscission of leaves and floral organs; during the release of seeds and pollen; during differentiation of root cap cells; and during fruit ripening. Each of these cell separation processes has its own distinctive features. Cell separation can also be induced during cooking or processing of fruit and vegetables, and the degree to which it occurs is a significant quality characteristic in potatoes, pulses, tomatoes, apples and other fruit. Control over these technological characteristics will be facilitated by understanding the role of cell adhesion and separation in the life of plants. [source]