Application of Atomic Layer Deposition of Cellulosic Materials Prepared Using 3D Printing Concepts

Abstract

Atomic layer deposition offers a 3-diemensional conformal deposition of materials along with the atomic scale control on thickness control at the low-temperature regimes. Metal oxide materials can be exploited to the nanoscale coating onto the underlying materials. The cellulose materials offer ecofriendly applications which can be designed to the versatile fabric products or equivalents. The integration of ALD onto the cellulose materials can be tailored towards stretchable electronics which allows the flexible deformation unlike the previous rigid applications based glass or silicon technologies. Zinc oxide (ZnO) is chosen to be a coating material characteristic of semiconducting conduction. The zinc oxide thin films are deposited through the atomic layer deposition of diethyl zinc (DEZ) water. The ALD-based zinc oxide thin films are characterized by a multitude of physical/chemical probing tools: X-ray photoelectron microscopy for bonding and composition information, X-ray diffraction for crystallinity, atomic force microscopy and scanning electron microscopy for morphological characterization, and dc/ac-based electrical characterizations. Cellulose and its derivatives are ecofriendly materials due to superior features tensile strength and toughness contrary to the pollution-inducing thermoplastic materials. The beneficial features are applied to building materials, pharmaceuticals, cosmetics, and foods. The cellulose-based materials are chemically versatile and artificially controlled. The current work exploits two specific features, i.e. i) the dissolution feature of cellulose acetate in acetone and the OH terminated features of cellulose materials. The flexible cellulose materials are prepared using a 3-dimensional printing concept: the cellulose acetate materials are dissolved intro acetone and the subsequent removal of acetone allows the flexible solid formation of cellulose materials after extrusion through high-resolution 3D-printing. The mesh-typed specimens are subjected to simultaneous measurements on mechanical deformation and electrical resistance. The electrical/dielectric monitoring is performed in the two-point electrode configuration involving ac and dc characterizations. In particular, the frequency-dependent impedance spectroscopy provides a wealth of information on bulk- and/or electrode-responses as a function of mechanical deformation. The applicability of ALD to cellulose materials is discussed in terms of mechanical robustness and electrical reliability required in high-performance stretchable electronics.