Conductive Ink with Circular Life Cycle for Printed Electronics

Abstract

Electronic waste carries energetic costs and an environmental burden rivaling that of plastic waste due to the rarity and toxicity of the heavy‐metal components. Recyclable conductive composites are introduced for printed circuits formulated with polycaprolactone (PCL), conductive fillers, and enzyme/protectant nanoclusters. Circuits can be printed with flexibility (breaking strain ≈80%) and conductivity (≈2.1 × 104 S m−1). These composites are degraded at the end of life by immersion in warm water with programmable latency. Approximately 94% of the functional fillers can be recycled and reused with similar device performance. The printed circuits remain functional and degradable after shelf storage for at least 7 months at room temperature and one month of continuous operation under electrical voltage. The present studies provide composite design toward recyclable and easily disposable printed electronics for applications such as wearable electronics, biosensors, and soft robotics.

Sequence Design of Random Heteropolymers as Protein Mimics

“…Utilizing and mimicking protein function is a key approach to unlocking advanced, robust, cheap, and scalable functional materials. Heteropolymers are routinely used for surfactants, − hydrogels, , polyelectrolytes, − gene delivery, − and more. − Chemistry diversification through monomer increments, side-chain modifications, or block copolymerization have been unsystematically explored as the primary design criteria for material functionalization. However, a more general chemical heterogeneity framework for rational design of protein-like heteropolymers is still lacking.…”

Stretchable, Biodegradable Dual Cross-Linked Chitin Hydrogels with High Strength and Toughness and their Potential Applications in Flexible Electronics

“…The full degradation times of E0Et80 and E0.3Et80 are calculated to be 115 and 121 d for E0Et80 and E0.3Et80 (see Figure S13b), respectively, indicating that chemical cross-linking slightly prolongs the degradation time of E0.3Et80, without hindering the process of degradation. Additionally, chitin materials exhibited rapid and almost complete degradation in Chitinase solutions, facilitating the separation and recovery of electronic substances, such as the precious metal silver. , Figure e shows photographs of various stages of gradual degradation and separation of the E0.3Et80-Ag flexible electrodes in Chitinase solution. Light microscopy images (Figure f) indicate the gradual increase and expansion of cracks, and degradation of floc at the surface and edges, followed by the gradual degradation into tiny fragments and nonforming slime.…”

Advances in 3D Gel Printing for Enzyme Immobilization

“…Another example using organic solvent systems involves the synthesis of random heteropolymers (RHP) with co-monomer distribution matching the protein surface pattern of the enzyme for stabilization and solubilization in organic solvents [ 86 ]. Xu and co-workers dissolved RHP-stabilized lipase together with PCL and a conductive filler for DIW of biodegradable electronic circuits [ 87 ]. The printed circuit remained functional and fully degradable, upon immersion in warm water, for at least 7 months at room temperature storage and after 1-month continuous exposure to electrical voltage.…”