HIGH PERFORMANCE PRODUCTS CREATED THROUGH MICROPATTERNED NANOCELLULOSE MATERIALS

摘要

Nanocellulose films with surface micropatterns have been fabricated by spray coating patterned silicon wafers. Cellulose-based materials are renewable, recyclable and environmentally friendly. If they are to replace high precision plastic-based components in areas such as electronics manufacturing, microfluidics and sensors, it is vital that these materials are able to be shaped and moulded in a reliable and cost-effective manner. Nanocellulose is a new class of materials consisting of cellulose fibres of diameters less than 100 nm, which has potential to be suitable for moulding applications. With the use of photolithography and deep reactive ion etching (DRIE), silicon moulds with channels widths of 5 to 500 um and depths of 6, 12 and 18 um were fabricated. Nanocellulose sheets were then formed by a rapid spray coating technique, which was developed within our group. Nanofibre suspensions were sprayed onto the moulds, which imparted the micropatterns onto the surface of the sheets. There were three well-defined regimes of conformation with the moulds: full conformation, partial conformation and no conformation. These regimes were driven by the aspect ratio (channel depth/width) of the moulds and demonstrates that the surface properties can be tuned to impart a controllable surface roughness. Within this work we have demonstrated micropatterned nanocellulose sheets for the first time. The use of spray coating allows this process to be easily scaled to industrially relevant volumes. The research reported here serves as the foundation for a new generation of environmentally friendly cellulose-based electronic and microfluidic devices.