285070 Future of the Layer-by-Layer Assembled Nanomaterials
Layer-by-layer assembly (LBL) is a very established field of materials engineering with multiple demonstrations of its utility and creative resolution of many interesting technological problems. It is important to understand better what could be the main directions of its future development. The key advantage of the technique is that it offers the possibility of multiscale engineering of nanocomposite materials based on sequential adsorption of nanometer scale layers of polymers and inorganic colloids. Using this property LBL can resolve hard challenges of materials science related to mechanical, electrical, optical, and biological properties. One of them is the design of materials with hard-to-reach combinations of electrical and mechanical properties necessary for energy conversion and storage characteristics. In this presentation, the principles of property engineering of these materials will be described. The focus technological areas will be (1) Flexible solar cells and solid state light emission devices; (2) High capacity lithium batteries; and (3) Biomedical implants with energy storage requirements. Manufacturing of such composites in large scale will also be addressed.
LBL films exhibit exceptional mechanical performance. This property becomes very essential in preparation of transparent conductors for flexible solar cells. One of the key hurdles on their mass utilization is replacement of expensive indium tin oxide coating, which also reveals deficient performance in bending, which is essential for flexible electronic devices. It will be demonstrated that the LBL films made from carbon nanotubes and appropriate polymers reveal cumulative figure of merit taking into account both electrical and mechanical performance higher than standard ITO glass. Surface conductivity of the coatings was as low as 80 Ohm/square.
Mechanical performance is essential for lithium ion batteries which is the key for attaining safety parameters. They are considered to be the main challenge for battery technologies in automotive and solar energy industries. It will be demonstrated that LBL films can achieve the combination of several characteristics enabling the new type of flexible Li+ batteries.
Biomedical implants must have many parameters similar to those needed in energy conversion with additional requirements for biocompatibility and biodegradability. LBL composites can satisfy all these stringent set of conditions. Preparation and functionality of a new type of implantable electrodes using LBL multilayers from carbon nanotubes and other materials will be demonstrated.
As a part of the future of LBL-made materials, the need to develop scaled-up versions of LBL deposition techniques is immediate and is expected to dominate the practical aspects of its realization. Some of the potential approaches to the resolution of this challenge and considerations for future devices in this area will be included in the presentation.
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