ELECtrical NANO-imPRINT for the industrial fabrication of nanoparticle-based sensors – ELECNANOPRINT

Many countries including France have recently launched ambitious R&D programs in order to promote the emergence of nanotechnologies. This strong interest is caused by the exploration of the innovative properties of nano-objects that could lead to many potential applications. For instance, the original properties of colloidal nanoparticles could be used in innovative sensors: their synthesis in solution in large quantities with low-cost chemical techniques is well controlled but the development of integration techniques enabling their directed assembly on surfaces is a technological lock-in restricting their use in functional electronic or mechanical systems.

The aim of the ELECNANOPRINT project is to bring a solution to this technological lock-in by demonstrating that the "electrical nanoimprint" process patented by the Laboratory of Physics and Chemistry of Nano-Objects (LPCNO) from Toulouse enables a low-cost mass production of nanoparticle-based sensors. The performances of such sensors are better than the conventional ones because of their extreme miniaturization, their low consumption and their high sensitivity.

This process already validated by a proof-of-concept consists in patterning a thermoplastic polymer electret layer both topographically and electrically in a single step: applying a conductive silicon mould with micro or nanometric patterns on a thermoplastic polymer electret layer heated above its glass transition temperature and applying an electric field to the mould/electret system results in charged patterns. Then, the immersion of such a patterned surface in a solution of colloidal nanoparticles leads to the selective trapping of nanoparticles in the charged patterns by electrostatic interactions: thousands of patterns with nanoparticles can thus be obtained in a few minutes in order to be used as sensor active areas.

To complete successfully this project and lead to the technology transfer of the developed processes and products, the LPCNO will be accompanied by the LAboratory on PLasma and Conversion of Energy (LAPLACE) and the technology transfer office of the Toulouse University Cluster for Higher Education and Research (VALO-PRES).The LAPLACE expertise in dielectric materials will be precious to understand the injection, trapping and charge transport mechanisms in films of polymer electrets on which "electrical nanoimprint" is based and thus converge faster to its optimization. Moreover, the VALO-PRES that has already worked with the LPCNO and thus knows the electrical nanoimprint invention, will identify companies interested by this technology in order to lead to license agreements.

The ELECNANOPRINT project will unfold in three main steps. The first step managed by the LAPLACE will aim at studying the injection, trapping and charge transport mechanisms on which "electrical nanoimprint" is based in order to optimize it. The second step managed by the LPCNO will be dedicated to the fabrication of several kinds of nanoparticle-based sensors including strain gauges and humidity sensors in order to demonstrate the industrial potential of "electrical nanoimprint". The third step managed by the VALO-PRES will aim at ensuring the technology transfer of the project results.