Transient electronics: Materials, mechanics, and applications

Transient electronics is an emerging field in materials science that has attracted considerable attention from the scholar community in the last few years. The unique attribute of transient technology is the capability to fully or partially disintegrate after a predefined period of stable operation. Transient electronics have a wide range of potential applications as biomedical implants, environmental sensors, and hardware-secured devices. Biodegradable transient sensors could be dissolved and absorbed into a bio-environment, eliminating complications associated with long-term presence of implanted devices, or secondary surgery to extract implanted devices. Eco-friendly environmental monitoring transient devices could be utilized to collect desired data, then degrade naturally into the surrounding environment, reducing the recollection expenses, and minimizing harmful waste. Self-deconstructing platforms could undergo disintegration and physically remove sensitive information once transience is triggered. Recent developments on transient materials, dissolution/disintegration mechanisms, manufacturing techniques, structural designs, and transient energy storage devices have advanced the functionality, performance, and applicability of transient electronics. Further research on precisely controlled transiency, however, is needed to broaden the applications of transient electronics. Since transient electronics are typically multilayer thin-film structures, to achieve controlled transiency at device level, it is crucial to understand the interfacial interactions among layers of dissimilar materials assembled on one another to form complex transient devices. This dissertation discusses materials, transiency mechanisms, and applications of transient electronics. Firstly, interfacial interactions among layers of dissimilar materials is systematically studied, revealing the mechanism of transiency achieved by swelling induced disintegration. Following section reports a transient battery utilizing swelling induced transiency as a proof-of-concept application. Lastly, the dissertation presents materials, mechanical properties, and applications of all-organic soft transient electronics. Firstly, to understand the underlying mechanism of swelling induced transiency, we studied interfacial interactions of a particular case of polymeric substrate with lithium titanate electrode coating layer. The structure is analogous to that of the anode in typical lithium-ion batteries; yet, can be extended to more general cases of soft electronics. This coordinated experimental-analytical-simulation study exhibited formation, accumulation and propagation of swelling-induced stress and fracture through the membrane-coating interface, when in transient mode. Swelling-induced stress as a function of electrode thickness was studied; the analytical data and simulations were verified by experimental results. Moreover, the fragment size of the electrode coating layer as a function of initial defect prevalence and distribution was investigated. The average fragment size was predicted using a combination of experimentally-determined initial defect distribution and finite element method-obtained swelling strain – defect length curve. The predicted average fragment size was found to be in good agreement with the experimental results. Meanwhile, as an application of swelling induced transiency, a transient lithium-ion battery based on polymeric constituents is presented. The battery takes advantage of a close variation of the active materials used in conventional lithium-ion batteries and can achieve and maintain a potential of \u3e 2.5 V. All materials are deposited form polymer-based emulsions and the transiency is achieved through a hybrid approach of redispersion of insoluble, and dissolution of soluble components in approximately 30 minutes. The reported transient battery could be applied an onboard power for transient electronics. In addition, a flexible all-organic transient sensor with potential to be applied as epidermal sensor is reported. A conductive conjugated polymer electrode was printed onto a water-soluble polymer substrate with an electrodehydrodynamic jetting printer. The all-organic electrode is partially transient with supportive substrate dissolved completely in water, while the conjugated polymer electrode remains intact. The intact functional electrode layer formed conformal contact with human skin and was applied as an epidermal strain sensor

Microfibers as Physiologically Relevant Platforms for Creation of 3D Cell Cultures

Microfibers have received much attention due to their promise for creating flexible and highly relevant tissue models for use in biomedical applications such as 3D cell culture, tissue modeling, and clinical treatments. A generated tissue or implanted material should mimic the natural microenvironment in terms of structural and mechanical properties as well as cell adhesion, differentiation, and growth rate. Therefore, the mechanical and biological properties of the fibers are of importance. This paper briefly introduces common fiber fabrication approaches, provides examples of polymers used in biomedical applications, and then reviews the methods applied to modify the mechanical and biological properties of fibers fabricated using different approaches for creating a highly controlled microenvironment for cell culturing. It is shown that microfibers are a highly tunable and versatile tool with great promise for creating 3D cell cultures with specific properties

Transient electronics: Materials, mechanics, and applications

Transient electronics is an emerging field in materials science that has attracted considerable attention from the scholar community in the last few years. The unique attribute of transient technology is the capability to fully or partially disintegrate after a predefined period of stable operation. Transient electronics have a wide range of potential applications as biomedical implants, environmental sensors, and hardware-secured devices. Biodegradable transient sensors could be dissolved and absorbed into a bio-environment, eliminating complications associated with long-term presence of implanted devices, or secondary surgery to extract implanted devices. Eco-friendly environmental monitoring transient devices could be utilized to collect desired data, then degrade naturally into the surrounding environment, reducing the recollection expenses, and minimizing harmful waste. Self-deconstructing platforms could undergo disintegration and physically remove sensitive information once transience is triggered. Recent developments on transient materials, dissolution/disintegration mechanisms, manufacturing techniques, structural designs, and transient energy storage devices have advanced the functionality, performance, and applicability of transient electronics. Further research on precisely controlled transiency, however, is needed to broaden the applications of transient electronics. Since transient electronics are typically multilayer thin-film structures, to achieve controlled transiency at device level, it is crucial to understand the interfacial interactions among layers of dissimilar materials assembled on one another to form complex transient devices. This dissertation discusses materials, transiency mechanisms, and applications of transient electronics. Firstly, interfacial interactions among layers of dissimilar materials is systematically studied, revealing the mechanism of transiency achieved by swelling induced disintegration. Following section reports a transient battery utilizing swelling induced transiency as a proof-of-concept application. Lastly, the dissertation presents materials, mechanical properties, and applications of all-organic soft transient electronics. Firstly, to understand the underlying mechanism of swelling induced transiency, we studied interfacial interactions of a particular case of polymeric substrate with lithium titanate electrode coating layer. The structure is analogous to that of the anode in typical lithium-ion batteries; yet, can be extended to more general cases of soft electronics. This coordinated experimental-analytical-simulation study exhibited formation, accumulation and propagation of swelling-induced stress and fracture through the membrane-coating interface, when in transient mode. Swelling-induced stress as a function of electrode thickness was studied; the analytical data and simulations were verified by experimental results. Moreover, the fragment size of the electrode coating layer as a function of initial defect prevalence and distribution was investigated. The average fragment size was predicted using a combination of experimentally-determined initial defect distribution and finite element method-obtained swelling strain – defect length curve. The predicted average fragment size was found to be in good agreement with the experimental results. Meanwhile, as an application of swelling induced transiency, a transient lithium-ion battery based on polymeric constituents is presented. The battery takes advantage of a close variation of the active materials used in conventional lithium-ion batteries and can achieve and maintain a potential of > 2.5 V. All materials are deposited form polymer-based emulsions and the transiency is achieved through a hybrid approach of redispersion of insoluble, and dissolution of soluble components in approximately 30 minutes. The reported transient battery could be applied an onboard power for transient electronics. In addition, a flexible all-organic transient sensor with potential to be applied as epidermal sensor is reported. A conductive conjugated polymer electrode was printed onto a water-soluble polymer substrate with an electrodehydrodynamic jetting printer. The all-organic electrode is partially transient with supportive substrate dissolved completely in water, while the conjugated polymer electrode remains intact. The intact functional electrode layer formed conformal contact with human skin and was applied as an epidermal strain sensor.</p

Ionic Liquid-Doped Gel Polymer Electrolyte for Flexible Lithium-Ion Polymer Batteries

Application of gel polymer electrolytes (GPE) in lithium-ion polymer batteries can address many shortcomings associated with liquid electrolyte lithium-ion batteries. Due to their physical structure, GPEs exhibit lower ion conductivity compared to their liquid counterparts. In this work, we have investigated and report improved ion conductivity in GPEs doped with ionic liquid. Samples containing ionic liquid at a variety of volume percentages (vol %) were characterized for their electrochemical and ionic properties. It is concluded that excess ionic liquid can damage internal structure of the batteries and result in unwanted electrochemical reactions; however, samples containing 40–50 vol % ionic liquid exhibit superior ionic properties and lower internal resistance compared to those containing less or more ionic liquids

Effect of Watering down Environmental Regulation on Residents&rsquo; Health in China: A Quasi-Natural Experiment of Local Officials&rsquo; Promotion Motivation

Environmental performance is increasingly important in promoting officials, whose pursuit of promotions and related behavior may affect the health of residents in their jurisdictions. In this study, we spatially matched Chinese river water quality monitoring station data, enterprise pollution emission data, and resident health data and quantified how Chinese officials pursuing promotions based on environmental performance affected resident health using a regression discontinuity design and difference-in-difference with interaction terms design strategy. The results show that the upstream&ndash;downstream disparity of environmental governance and pollutant emissions affects the residents&rsquo; health, medical treatment behavior, and medical expenditure. Furthermore, we identified the causal relationship between official promotion and upstream&ndash;downstream disparity and estimated the marginal effect of promotion on residents&rsquo; health. The study suggests that local officials limit the pollution emissions of enterprises in the upstream river to achieve environmental performance and relax the pollution restrictions of firms in the downstream river to achieve economic performance, such that the health of residents near the river is differentially affected

Effects of Decentralized Water Regulation on Agriculture in China: A Quasi-Natural Experiment Based on Incentives for Promoting Officials

Environmental performance is becoming increasingly essential for promoting local officials in China; thus, their pursuit of promotion may affect agricultural output. This study spatially matched Chinese local official promotion data, regional agricultural output, river-water-quality-monitoring stations, and riverside enterprise discharge data. Based on the difference-in-difference model, the exogenous impact of the natural experiment based on the promotion of officials is quantified as how the promotion behavior of local officials in pursuit of environmental achievements affects agricultural output. This was examined under the decentralization system of China&rsquo;s environmental governance. The results show that local officials improve agricultural production by controlling environmental pollution through promotion incentives. However, since the central government can observe the regulatory effect of upstream officials through the readings of water monitoring stations, upstream officials strictly enforce the central environmental regulations due to promotion motivation, while downstream officials do not strictly enforce their counterparts. This can result in differentiated impacts on agriculture in upstream and downstream regions. We also carried out a parallel test, placebo test, and measurement error test for the quasi-natural experiment, and the conclusions derived from the analysis remained robust. Our study has important implications for designing compatible environmental governance contracts and incentive policies for promoting agricultural production

A Composite Porous Membrane Based on Derived Cellulose for Transient Gel Electrolyte in Transient Lithium-Ion Batteries

The transient lithium-ion battery is a potential candidate as an integrated energy storage unit in transient electronics. In this study, a mechanically robust, transient, and high-performance composite porous membrane for a transient gel electrolyte in transient lithium-ion batteries is studied and reported. By introducing a unique and controllable circular skeleton of methylcellulose to the carboxymethyl cellulose-based membrane, the elastic modulus and tensile strength of the composite porous membrane (CPM) are greatly improved, while maintaining its micropores structure and fast transiency. Results show that CPM with 5% methylcellulose has the best overall performance. The elastic modulus, tensile strength, porosity, and contact angle of the optimized CPM are 335.18 MPa, 9.73 MPa, 62.26%, and 21.22°, respectively. The water-triggered transient time for CPM is less than 20 min. The ionic conductivity and bulk resistance of the CPM gel electrolyte are 0.54 mS cm−1 and 4.45 Ω, respectively. The obtained results suggest that this transient high-performance CPM has great potential applications as a transient power source in transient electronics

Transient Electronics as Sustainable Systems: From Fundamentals to Applications

The unique attribute of transient technology is that it promotes the potential for the design and implementation of sustainable systems through their capability to fully or partially disintegrate after a predefined period of stable operation. Transient electronics have a wide range of potential applications as biomedical implants, environmental sensors, and hardware-secured devices. Controlled disintegration of such systems without the need for harsh solvents is a step toward realizing green and sustainable electronics. In this short review, recent progress in the development of transient electronics is studied. First, an overview of the transient materials, both the substrate and electronic component, is described. Second, the mechanisms under which transiency occurs, including aqueous dissolution and thermal degradation, are reported. Third, manufacturing techniques for the fabrication of transient electronics are reviewed. And last, various transient electronic devices and their applications are discussed.This is the peer-reviewed version of the following article: Jamshidi, Reihaneh, Mehrnoosh Taghavimehr, Yuanfen Chen, Nicole Hashemi, and Reza Montazami. "Transient Electronics as Sustainable Systems: From Fundamentals to Applications." Advanced Sustainable Systems 6, no. 2 (2022): 2100057, which has been published in final form at DOI: 10.1002/adsu.202100057. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Copyright 2021 The Authors. Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Posted with permission.

Transient bioelectronics: Electronic properties of silver microparticle-based circuits on polymeric substrates subjected to mechanical load

Transient soft bioelectronics are capable of forming conformal contacts with curvilinear surfaces of biological host tissues and organs. Such systems are often subject to continuous static and dynamic loads from the biological host. In this article, we present investigation of electronic attributes of transient soft bioelectronic circuits subjected to mechanical force and influence of substrate's transiency on the transiency of the whole device; also, characterize and quantify loss of functionality in triggered devices. Variations in the electrical conductivity of circuits as a function of applied mechanical load was used as a means to deduce electronic characteristics under stress. The experimental results suggest that there exists a correlation between electronic properties of circuits and applied mechanical strain; no clear correlation was, however, observed between electronic properties of circuits and frequency of the applied dynamic load. Control over transiency rate of identical circuits utilizing the transiency characteristics of the poly(vinyl alcohol)l‐based substrates is also studied and demonstrated