Hot embossing and thermoforming of biodegradable three-dimensional wood structures

Abstract

Hot embossing allows for low cost fabrication of nanostructures with highest aspect ratios on large surfaces and is commonly based on a large variety of polymers. The widespread use of nanostructured materials, however, poses environmental challenges. Here, we show that biodegradable wood from renewable resources can be structured on the nano-scale and that surface characteristics can be imprinted and three-dimensionally formed. In particular, we show that so-called liquid wood made out of lignin can be structured with feature sizes down to 100–200 nm and three dimensionally shaped by microthermoforming. We demonstrate optical active surfaces by diffractive elements, the change of hydrophobic to super-hydrophobic behavior and the fabrication of super-hydrophobic microfluidic channels. Based on these results we anticipate new applications in the nano- and micro-range, particularly for use in sensitive environments without posing a risk to nature. The new compound material will allow for a substitution of conventional polymers used as material in one way applications of e.g. the consumer, the food or the disposable medical industry.