Researchers led by Prof. CHEN Tao at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences have proposed a facile approach to develop elastic and conductive Janus membranes with excellent adhesion for advanced flexible multifunctional electronics. The study was published in Chemistry of Materials. 

Thanks to the portable, flexible, and soft features, wearable electronics have drawn tremendous attention among researchers, especially in the field of mobile health monitoring, human machine interaction, and soft robotics. However, developing skin-like membranes with enhanced interfacial conformality and adhesion via a facile and efficient approach still remains challenging. 

Marine organisms such as barnacles can realize strong adhesion by virtue of the secretion of proteins. Specifically, the barnacle secretes mucus to fully wet the topological surfaces, and then the mucus condenses into a gelatinous layer with high adhesion after several hours of curing.

Inspired by barnacles, the researchers of NIMTE prepared carbon nanotubes (CNTs)/Ecoflex Janus membrane on the water surface through interfacial assembly. Subsequently, the membrane experienced a two-step curing process, including partial curing for full spreading on substrates and complete curing for enhanced conformal adhesion. 

According to the researchers, the Janus membrane can be further integrated into wearable conformal electronics, thus realizing effective and stable detection of conventional unidirectional bending deformation as well as high-efficiency differentiation of the reverse fine deformation.

In addition, the developed wearable electronics can highly adapt to the hierarchically wrinkled paper surface, enabling real-time dynamic detection of the paper-folding behavior. 

As a proof of concept, an artificial wrinkled trunk based on the Janus membrane was designed for bidirectional bending deformation monitoring and motion differentiation. 

This study on the bioinspired membrane with enhanced adhesion may shed light on the facile and efficient fabrication of multifunctional wearable electronics and soft robotics. 

This research was supported by the Natural Science Foundation of China, the Open Research Projects of Zhejiang Lab, and the Sino-German Mobility Program, etc. 

The bioinspired conformal and adhesive membrane. (Image by NIMTE)