Stretchable, bendable and foldable electronics are central to the development of emerging technologies like adaptive displays, artificial skin, and biometric and wearable devices. This presents a unique challenge of balancing electronic performance and mechanical flexibility. The researchers say the difficulty lies in finding a material that can withstand a range of deformations, like stretching, bending and twisting, all while maintaining electrical conductivity. Adding to the challenge is the need to engineer this conductivity into a variety of different surfaces, such as cloth, fibre, glass or plastic.
The team chose two-dimensional metal carbides (MXenes) as the main focus of the research as previous research has shown them to have a metallic-like conductivity. The previous research on MXenes has focused primarily on the materials in the form of sheets. Although these sheets have the desired conductivity, they are not stretchable, nor have they been integrated into different surfaces.
Rather than using MXene sheets, the Texas team created MXene coatings through the sequential adsorption of negatively charged MXene sheets and positively charged polyelectrolytes using an aqueous assembly process known as layer-by-layer assembly (See main image - section A). The results of this process are said to demonstrate that MXene multilayer coatings can undergo large-scale mechanical deformation while maintaining a high level of conductivity. The team has also successfully deposited the MXene multilayer coatings onto flexible polymer sheet, stretchable silicones, nylon fibre, glass and silicon.
