Argon plasma irradiation of polypropylene

a b s t r a c t Polypropylene samples were exposed to argon plasma discharge and the changes of the PP surface properties were studied by different methods. Surface wettability was derived from contact angle measured by standard goniometry and chemical structure of the plasma modified PP was studied using X-ray photoelectron spectroscopy (XPS) and by Rutherford backscattering spectroscopy (RBS), surface morphology and roughness of samples using AFM. Zeta potential of pristine and modified PP was determined with the SurPASS. The presence of incorporated oxygen in the PP surface layer, about 60 nm thick, was observed in RBS spectra. Oxygen concentration is a decreasing function of the depth. With progressing aging time the oxygen concentration on the PP surface decreases. Plasma treatment results in a rapid decrease of the contact angle, which increases again with increasing aging time. In XPS measurement the oxygen containing structures, created by the plasma treatment, were found on the very surface of the modified PP and the zeta potential being changed too. The significant difference in zeta potential between pristine and plasma treated PP clearly indicates that the plasma treatment leads to a more hydrophilic PP surface

Chitosan/glycosaminoglycan scaffolds for skin reparation

Burns and chronic wounds, often related to chronic diseases (as diabetes and cancer), are challenging lesions, difficult to heal. The prompt and full reconstitution of a functional skin is at the basis of the development of biopolymer-based scaffolds, representing a 3D substrate mimicking the dermal extracellular matrix. Aim of the work was to develop scaffolds intended for skin regeneration, according to: fabrication by electrospinning from aqueous polysaccharide solutions; prompt and easy treatment to obtain scaffolds insoluble in aqueous fluids; best performance in supporting wound healing. Three formulations were tested, based on chitosan (CH)and pullulan (P), associated with glycosaminoglycans (chondroitin sulfate - CS or hyaluronic acid \u2013 HA). A multidisciplinary approach has been used: chemico-physical characterization and preclinical evaluation allowed to obtain integrated information. This supports that CS gives distinctive properties and optimal features to the scaffold structure for promoting cell proliferation leading tissue reparation towards a complete skin restore

Characterization of Biomedical Surfaces by Streaming Potential Measurements

The knowledge of surface charge and the isoelectric point is important for many biomedical applications. [...

TEMPERATURE DEPENDENCE OF LUMINESCENCE DECAY FROM THE 1G52 STATE OF Sm3+ IN Cs2NaSmxΥ1 -x Cl6 AND Cs2NaSmxEuyΥ1-x-yCl6

Luminescence decay curves for the 4G5/2 →6Η7/2 emission of Sm 3 + in the cubic hexachloroeIpasoIite crystals Cs2ΝaSmxY1-xCl6 (x = 0.005 to x = 1) and Cs2ΝaSmxΕu Y1-x-yCl6 (x = 0.01 to x = 0.95, y = 0.05 to y = 0.99) have been measured over the temperature range 10 K to 300 K using pulsed laser excitation into the 4G5/2 state of Sm3+ . The luminescence from this state is strongly quenched by cross relaxation to Sm3+ acceptors and energy transfer to the 5D0 state of Ευ3+ Tle temperature dependence of cross relaxation and of energy transfer is discussed in terms of the involved mechanisms