With the ever-growing demand for renewable energy sources, energy harvesting from natural resources has gained much attention. Energy sources such as heat and mechanical motion could be easily harvested based on pyroelectric, thermoelectric, and piezoelectric effects. The energy harvested from otherwise wasted energy in the environment can be utilized in self-powered micro and nano devices, and wearable electronics, which required only µW–mW power. This article reviews pyroelectric energy harvesting with an emphasis on recent developments in pyroelectric energy harvesting and devices at micro/nanoscale. Recent developments are presented and future challenges and opportunities for more efficient materials and devices with higher energy conversion efficiency are also discussed.

We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM)-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.