Cellulose nanofibrils and silver nanowires active coatings for the development of antibacterial packaging surfaces

An active ink composed of cellulose nanofibrils and silver nanowires was deposited on flexible and transparent polymer films using the bar coating process, achieving controlled thicknesses ranging from 200 nm up to 2 µm. For 350 nm thick coating on polyethylene terephthalate films, high transparency (75.6% transmittance) and strong reduction of bacterial growth equal to 89.3% and 100% was noted respectively against Gram-negative Escherichia Coli and Gram-positive Staphylococcus Aureus bacteria using AATCC contact active standard test. Retained antibacterial activity was found with films produced by reverse gravure roll-to-roll process, showing the promising capability of this antibacterial solution to be deployed industrially. Finally, the same ink was also deposited on polylactic acid substrate to investigate barrier properties: for 350 nm thick coating, a reduction of 49% of oxygen transmission rate (dry conditions) and 47% reduction of water vapor transmission rate was noted, proving the enhanced barrier properties of the coatings

Hybrid system to develop transparent and conductive ink

International audienceNowadays, conductive and transparent materials are limited. The main material is In-dium Tin Oxide (ITO). Despites their excellent property in terms of transparency and con-ductivity, ITO is brittle and not easily processable to produce patterns for radio-frequencies applications for example. To answer this problematic, we propose in this study a new solution with an ink, formulated with nanocellulose and a conductive material, for screen-printing application. The oxidized cellulose nanofibrils used have multiple roles: i) as a transparent matrix with adapted rheological properties, ii) as an adhesion link between the substrate and the silver nanowire iii) as a dispersing agent to favor the nanostructured network of the conductive material. The hybrid system has been characterized by AFM, SEM-FEG, rheometer and the final antenna by anechoic chamber. The ink developed present new results with a high conductivity (Rs70% @550nm) by keeping adapted rheology properties (G’ and G”). These results allow printing of conductive and transparent pattern usefull for various applications

Influence of mesh geometries on the design of transparent antennas at 2.45 GHz

International audienceThis paper presents optically transparent dipole antennas with innovative meshes for printing processes. The influence on antenna performance of the meshing geometry, the width and the pitch of dipole are investigated. The study shows that, for a given width, an increase of the performance with a twin small pitch with circle geometry. Furthermore, the antennas with an optical transparency of 70% present a loss of the realized gain around 0.35% compared to an opaque conventional dipole antenna with the same width

PEDOT-PSS coating on specialty papers: process optimisation and effect of surface properties on electrical performances

International audienc

Inkjet printing of conductive nanocellulose inks for flexible electronics

International audienc

Optically and Flexible Transparent Screen-Printed Rectenna for Wireless Energy Harvesting

International audienc

Design and study of meshed and optically transparent dipole antennas at 2.45 GHz

International audienc

Development of Flexible & Quasi-Optically Transparent CPW Antennas for 5G by Meshing Construction

International audienceThis paper presents optical transparent CPW antennas designed for 5G telecommunications obtained by an additive printing process. This optical transparency has been obtained by meshing the antenna. The influence of the meshing strategy on the antenna performances is explored, by investigating two geometrical models of antennas and in three different meshing. The adaptation, radiation performance and optical transmittance have been characterized. The best trade-off between transparency and radiation performance is presented through a plot connecting the realized gain and the optical transparency. The square meshing features the best trade-off with more than 65% of optical transparency for 2 dBi in realized gain