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

在过去的十年中，功能性纳米复合材料在包括氢燃料电池、太阳能电池、组织工程等可持续能源技术在内的各个领域发挥着至关重要的作用。它们可以提供相应的散装材料无法达到的性能。目前的重点是控制它们的组成、形态、纳米结构和功能，以及它们的特定应用。该研究计划的目标是开发可控制形态/功能的纳米复合材料和生物相容性复合材料，特别是为染料敏化太阳能电池（DSSC）光阳极、质子交换膜燃料电池（PEMFC）电极和双极板（BPPs）以及用于软骨组织再生的生物相容性支架而设计。***目前，软骨多孔支架一旦开发出来，需要进一步的溶剂处理，在孔内添加生物相容性材料，以促进细胞增殖，从而导致不必要的残留溶剂。在第一个主题中，我们提出了一种无溶剂技术来开发开放细胞支架，将壳聚糖（一种生物相容性/可生物降解的天然聚合物）修饰并在支架发泡时直接投射在孔表面，从而通过壳聚糖修饰产生强附着力。**** DSSC光阳极中二氧化钛（TiO2）层的传统制造工艺需要高温烧结，导致其结构脆性。那么柔性结构的发展，这是本提案中第二个主题的对象，是一个挑战。基于我们在纳米结构TiO2合成方面的专业知识，我们将使用室温静电纺丝技术从含有TiO2- cds纳米颗粒的聚合物基质中开发出具有可控制尺寸和形状的柔性纤维纳米结构。主要目的是通过提供更大的光阳极表面积和增加与光敏染料的电子转移来增加光阳极的柔韧性和电池效率。****作为本提案的第三个研究主题，我们将使用最近设计的与ARES流变仪兼容的实验装置，以研究共连续形态纳米复合材料在结晶动力学方面的电导率行为的“在线”演变。这将有助于我们优化纳米复合材料的冷却剖面，以获得更高的导电性。我们还将进行一项原创研究，其中我们将调查动态剪切对熔融聚合物/聚合物体系电导率的影响。我们的研究目标是降低导电添加剂的阈值浓度，从而提高纳米材料的可加工性和导电性，特别是聚合物基PEMFC电极和bpp。＊＊＊＊＊

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 first*theme a solvent-free technique to develop open cell scaffolds where chitosan, a biocompatible/biodegradable*natural 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. *****