Electronic waste (e-waste) from nonbiodegradable products present a significant global problem due to its toxic nature and substantial environmental impact. In this study novel electrically conductive biodegradable films of uncured natural rubber (NR) incorporating graphite platelets and chitosan were developed via a latex aqueous microdispersion method. Chitosan was added as a dispersing and thickening agent to encourage the uniform distribution of graphite in the NR matrix at loadings of 20-60 parts per hundred rubbers (phr). FTIR confirmed interactions between NR, graphite, and chitosan. FE-SEM and Synchrotron XTM analyses demonstrated uniform graphite dispersion. The result of XRD revealed the greatest crystallinity at 86.9% with 60 phr graphite loading. Mechanical properties testing indicated a significant increase in Young's modulus to 58.2 MPa, or about 470-fold improvement over the pure NR film. The composite films demonstrated improved thermal and chemical resistance, and their electrical conductivity could rise dramatically to 1.22 x 10-5 S cm-1 at 60 phr graphite loading, or about six orders of magnitude higher than pure NR film. The composite films exhibit antibacterial activity against Staphylococcus aureus and some inhibition against Escherichia coli. In addition, the NR composite films exhibited biodegradability ranging from 16.7% to 25.1% after three months of soil burial, declining with increased graphite loading. These results demonstrate the potential of NR-graphite composites as conductive materials for flexible electronics, such as thin-film electrodes in energy storage devices and sensors.

Skin-like bioelectronics offer a transformative technological frontier, catering to continuous and real-time yet highly imperceptible and socially discreet digital healthcare. The key technological breakthrough enabling these innovations stems from advancements in novel material synthesis, with unparalleled possibilities such as conformability, miniature footprint, and elasticity. However, existing solutions still lack desirable properties like self-adhesivity, breathability, biodegradability, transparency, and fail to offer a streamlined and scalable fabrication process. By addressing these challenges, inkjet-patterned protein-based skin-like silk bioelectronics (Silk-BioE) are presented, that integrate all the desirable material features that have been individually present in existing devices but never combined into a single embodiment. The all-in-one solution possesses excellent self-adhesiveness (300 N m-1) without synthetic adhesives, high breathability (1263 g h-1 m-2) as well as swift biodegradability in soil within a mere 2 days. In addition, with an elastic modulus of approximate to 5 kPa and a stretchability surpassing 600%, the soft electronics seamlessly replicate the mechanics of epidermis and form a conformal skin/electrode interface even on hairy regions of the body under severe perspiration. Therefore, coupled with a flexible readout circuitry, Silk-BioE can non-invasively monitor biosignals (i.e., ECG, EEG, EOG) in real-time for up to 12 h with benchmarking results against Ag/AgCl electrodes.

In recent years, organic electronics have been explored as a potential paradigm for renewable, transient, and biodegradable systems. In this study, we used fish scales as raw materials for fabricating a biopolymer substrate (BPS) and evaluated its application in an organic metal-insulator-metal capacitor. Evaluation of the morphological and optical properties of BPS revealed an average surface roughness value of 1.19 nm, 90% transmittance in the UV-visible range, and an absorption coefficient of 5.29 cm(-1) at 3.5 eV. Fourier transform infrared spectroscopy showed the presence of amide A, amide I, amide II, and amide III bonds in the substrate, and 42 degrees +/- 5 degrees was the rollover contact angle. The substrate was dissolved in water within 40 min at room temperature and degraded by more than 90% within 30 days in natural soil. Further, mechanical property analysis showed that the substrate exhibited a flexural strength of 8.33 MPa and a tensile strength of 4 MPa. The capacitance density and leakage current of the Al/bovine serum albumin/Pt/BPS structure are found to be 1.05 fF/mu m(2) (1 MHz, 1 V) and 1.15 mu A/cm(2) (at 1 V), respectively. The proposed substrate can be used as a cost-efficient, ecofriendly, biocompatible, and transparent charge storage device for transient electronics in the near future.