Polyhydroxyalkanoates for Biodegradable Printed Circuit Boards: A Mini Review for Bio-Microelectronics

Abstract

Printed circuit boards (PCBs) are essential components of nearly all electronic products and consist mostly of laminated structures combining conductive and insulating layers. Conventional PCB manufacturing relies on fossil-based and poorly degradable materials. Most widely used components are the fiberglass FR-4 for rigid substrates and polyethylene terephthalate (PET) for flexible substrates. When improperly managed at the end-of-life stage, PCBs pose significant environmental and health risks. Current disposal practices, including incineration and e-waste storage, contribute to the release of carcinogenic and persistent pollutants such as dioxins and polycyclic aromatic hydrocarbons, with severe impacts on ecosystems and human health. Consequently, there is an urgent need to develop simplified recycling strategies and to adopt environmentally friendly materials for both substrates and processing reagents. Polyhydroxyalkanoates (PHAs) represent a promising class of biopolymers synthesized by microorganisms. PHAs combine functional performance with intrinsic biodegradability and enable controlled degradations of electronic substrates after disposal. In recent studies, PHAs were investigated as sustainable PCB substrate materials, processed through additive manufacturing techniques such as drop casting, spray coating, inkjet printing, and laser activation to support material-efficient and low-impact fabrication routes. The surface morphology and topography of the surface of the substrates were characterized using optical profilometry, while cross-section analyses and scanning electron microscopy were employed to evaluate layer integrity, microstructure, and interfacial quality. Thermal properties were evaluated by thermogravimetric analysis. In addition, eco-friendly solvent-based approaches were explored for the recovery and recycling of materials, aiming to close the material loop and enhance circularity. Overall, the integration of biodegradable polymers, advanced manufacturing techniques, comprehensive material characterization, and green recycling strategies suggest viable pathways toward environmentally responsible microelectronics and support the transition to a more sustainable future for electronic materials.