Materials and structural innovations for bioelectronics and soft actuators

Over the past few decades, technological advances have drastically altered people's lifestyles. One of the most relevant tech breakthroughs to everyday individuals is the commercialization of wearable devices. These gadgets enable long-term, real-time health, and sports monitoring, allowing people to manage their well-being more efficiently. Moreover, medical professionals can better understand disease phenotype and progression. Soft electronic materials are at the core of wearable devices, and their development will determine the scope and depth of future applications. Scientists have been deeply involved in flexible electronic materials/devices for years and have developed various conductive and semiconductor materials adaptable to large deformation, stretchable, and bendable. The processing methods of flexible electronic materials are generally divided into two types. One is to directly process stretchable and bendable conductive and semiconductor materials, such as soft conductive polymers, soft conductive composite materials, and so on. The other way is to convert rigid traditional electronic products into stretchable devices by processing stretchable two-dimensional or three-dimensional structures. The main research interest in this dissertation focuses on the development of stretchable structures and functions involving 3D structures processed using self-assembly methods, which convert two-dimensional primary deformations into three-dimensional deformations, which can significantly strengthen materials' stretchability, such as turning the original non-stretchable polymer material into a three- dimensional structure device that can withstand considerable strain ([greater than] 100 percent). Through the functional development of 3D structures, I have realized 3D stretchable conductive circuits and supercapacitor energy storage devices based on laser-induced graphene in the first project, and the stretchability of these devices exceeds 100 percent. I have also developed soft actuators with laser-induced graphene heaters and polymer substrates. I used the actuators to achieve more complex three-dimensional deformation, such as on-demand physiological signal acquisition systems, anti-resonance processing metamaterials, etc. 3D structures can also be used to process biomimetic materials. The third project introduces the use of 3D designs to realize cardiac muscle's nonlinear mechanical and electrical properties, which provides new ideas for the research and development of biomimetic muscle materials. Finally, I realized a new type of on-skin bioelectronic interface through a 2D stretchable structure and polylysine-modified PDMS attached to it, which has rich functions such as antibacterial, breathable, light-transmitting, and non-linear mechanical properties. To conclude, this paper highlights my research innovations and achievements in developing stretchable structures and materials, many of which have significant scientific and practical value.