Functional surfaces that can be widely used in next-generation electronic devices, sensors, and smart wear must be able to recover to their original state after deformation, resist wetting, exhibit high optical properties, and offer adhesive characteristics that allow attachment to various substrates. To realize these features, the research team led by Seong-Jun Park, Professor at Jeonbuk National University (JBNU) (College of Engineering, Department of Polymer -Nano Science &Technology and Department of Nano Convergence Engineering), announced on the 13th that it has succeeded in fabricating a plastic double-layer film composed of a rigid upper layer and a flexible lower layer.

This research outcome was published in the latest issue of <Applied Materials Today> (IF=10.041) and was also selected as the cover article for the August issue. Yu-mun Wi, a doctoral student in the Department of Nano Convergence Engineering, is the first author, and Si-yeon Kim, a master's student, is the second author.

The double-layer film produced by Professor Park's team is characterized by the reversible formation and disappearance of hair-width wrinkled patterns on the surface in response to heat, light, and electrical energy.

To fabricate this double-layer film, the team dispersed and embedded a liquid metal (gallium, melting point 29.8°C) filler into the flexible lower layer, enabling rapid actuation of the formation and disappearance of the wrinkled patterns.

Applications are expected to include smart windows that attach to building glass to control sunlight transmittance and save energy, and functional films that can freely adhere and detach under various thermal conditions while exhibiting strong resistance to wetting.

Professor Park stated, “This material is very easy to fabricate and can be readily formed into fine wrinkled patterns with widths on the order of a human hair or restored to its original state by various thermal energies. It can be widely applied in smart electronic devices, sensors, and electronic textiles in the future.”

Meanwhile, this research was carried out with support from the National Research Foundation of Korea through its Excellent Young Researcher Program and the Basic Research Laboratory Program.