The application of inert and insulating low density polyethylene (LDPE) in electrochemical detection is null. However, in a recent study it was found that reactive species formed onto the surface of plasma-treated LDPE and other polymers promote the electrocatalytic oxidation of dopamine. In this work, we examine the role of plasma-treated LDPE as mediator in enzymatic glucose biosensors based on Glucose oxidase and glass carbon substrate. Results indicate that plasma-induced changes facilitate the electrocommunication between the enzyme and the substrate. The chronoamperometric response of these sensors prove their bifunctionality since the oxidation of glucose to gluconolactone, which is catalyzed by the GOx, coexists with the oxidation of dopamine that is electrocatalytized by the plasma activated LDPE surface.
"This is the peer reviewed version of the following article: Buendía JJ, Fabregat G, Castedo A, Llorca J, Alemán C. Plasma-treated polyethylene as electrochemical mediator for enzymatic glucose sensors: Toward bifunctional glucose and dopamine sensors. Plasma Process Polym. 2017;e1700133, which has been published in final form at https://doi.org/10.1002/ppap.201700133. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
Calcium phosphate cements (CPCs) are extensively used as synthetic bone grafts, but their poor mechanical properties limit their applicability to non-stress-bearing applications. The aim of the present work is to evaluate the potential of plasma surface modification of polylactide (PLA) fibers for reinforcement of CPCs. Oxygen low-pressure plasma was employed at different treatment times and the surface properties of the untreated and plasma-treated PLA were evaluated. Plasma treatment on the PLA fibers reduced the setting times of the PLA-CPC composites and improved their flexural properties.
Typical results quantifying the antibacterial efficiencies of high and reduced pressure nitrogen afterglows are presented, using the same microbiological protocol. In parallel, the diffusion of
the nitrogen atoms through different polymer membranes is studied.
Plasma sterilization has been extensively studied in recent years, and at present conditioning materials such as sterilization pouches or process indicators devoted to such processes should be optimized to allow transfer of the technology to the market. The present work evaluates the possibility of using wettability modification of hydrophobic textiles to detect whether Natoms
of a flowing post-discharge in sterilization conditions (1 L/min, 100W) are able to freely cross a cellulose membrane (found on the permeable side of a conventional sterilization pouch) and exert their action. Results showed that N2 postdischarge
treatment did not alter pore size of the
membrane, and the use of tailored hydrophobic
textiles was shown to be an appropriate indicator of N atom penetration inside the pouches. Depending on the initial hydrophobic treatment of the textiles, it is possible to detect differences in the density of atoms which crossed the membrane,
being capable of distinguishing between
parameters such as treatment time, or altered
hydrodynamics of the chamber.
In this study, the contact fatigue behavior of a PVD TiN coating deposited onto DIN 1.2379 coldwork
tool steel is assessed by cyclic spherical indentation. Experimental characterization
focuses on the evaluation of critical contact pressures, under both monotonic and cyclic
loading, affiliated to the emergence of distinct damage events: circumferential cracking and
cohesive spallation at the film or decohesion at the substrate–coating interface. Experimental
findings indicate that the coated tool steel studied is susceptible to mechanical degradation
under fluctuating contact loads, and the corresponding effective fatigue sensitivity varies
depending on the mechanism recalled for defining critical damage.
Canal, C.; Gaboriau, F.; Vílchez, A.; Erra, P.; García-Celma, M.J.; Esquena, J. Plasma processes and polymers Vol. 6, num. 10, p. 686-692 DOI: 10.1002/ppap.200950011 Data de publicació: 2009 Article en revista
The aim of this study was to evaluate the morphological characteristics and wetting properties of polystyrene-divinylbenzene (PS-DVB) solid foams and their modification through post-discharge plasmas. The low-density solid foams are mainly macroporous, but show a small fraction of mesopores; their characterization revealed differences in topography between the smoother surface and the rougher bulk, while from the chemical point of view both regions of the PS-DVB solid foams are hydrophobic. The macroporous structure of these materials with high pore volume makes them interesting for the design of new drug delivery systems, but some active principles and the physiological media are hydrophilic; therefore, it would be of interest to modify the wettability of the materials via post-discharge plasma treatments.