Development of high functionality composites and nanocomposites for tissue engineering and energy conversion systems

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During the last decade, functional nanocomposites are set to play a crucial role in various areas including sustainable energy technologies such as, hydrogen fuel cells, solar cells, tissue engineering, etc. They can offer performances that are not reachable by their corresponding bulk materials. The emphases are presently placed on the control of their composition, morphology, nanostructure and functionality with respect to their specific applications. The aim of the proposed research program is to develop controlled morphology/functionality nanocomposites and biocompatible composites particularly designed for dye-sensitized solar cell (DSSC) photoanodes, proton exchange membrane fuel cells (PEMFC) electrodes and bipolar plates (BPPs), and biocompatible scaffolds for cartilage tissue regeneration. Presently, cartilage porous scaffolds, once developed, need a further solvent treatment to add biocompatible materials inside the pores in order to promote cell proliferation, leading to unwanted residual solvents. We propose in this firsttheme a solvent-free technique to develop open cell scaffolds where chitosan, a biocompatible/biodegradablenatural polymer, is modified and directly projected on the surface of the pores during scaffolds' foaming, leading to strong adhesion thanks to chitosan modification.The conventional manufacturing process of Titanium dioxide (TiO2) layer in DSSC photoanode requires a high temperature sintering, leading to a brittle structure. Then the development of flexible structures, object of the second theme in this proposal, is a challenge. Based on our expertise in the synthesis of nanostructured TiO2, we will use room temperature electrospinning technique to develop flexible fibrous nanostructures from a polymeric matrix containing TiO2-CdS nanoparticles of controlled size and shape. The main objective is to increase photoanode flexibility and cell efficiency by providing large photoanode surface area and increased electron transfer with the photosensitizing dye.As third research theme in this proposal, we will use a recently designed experimental setup compatible with our ARES rheometer in order to investigate the 'online' evolution of the electrical conductivity behavior in co-continuous morphology nanocomposites with respect to their crystallization kinetics. This will help us to optimize the cooling profile of the nanocomposites in order to attain higher electrical conductivity. We will also undergo an original study in which we will investigate the effect of dynamic shearing on the electrical conductivity of melted polymer/polymer systems. We aim from this study to decrease the threshold concentration of the conductive additives and consequently increase nanomaterials' processability and electrical conductivity, particularly needed for polymer-based PEMFC electrodes and BPPs.