Ecofriendly Polymer-Graphene-Based Conductive Ink for Multifunctional Printed Electronics

The ongoing research on printed and flexible electronics is primarily focused on conductive three-dimensional (3D) print patterning. However, due to the nonhomogeneous distribution of conductive elements in a polymer matrix and their tendency to shrink, 3D-printed patterns often suffer from low-printing accuracies and poor mechanical and electrical properties. Here, poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVBVA) is reinforced with microwave-exfoliated graphene to develop a conductive ink for 3D printing. Compared with the pure PVBVA patterns, the PVBVA/graphene patterns exhibited a high-electrical conductivity, a twofold enhancement in tensile strength, an improved printing accuracy, and a high stability because of the graphene addition. The PVBVA/graphene inks flowed well during the printing; loading of up to 0.1 wt% graphene in the PVBVA gel resulted in notable changes in the rheological properties of the ink. The printed conductive patterns showed a high flexibility suitable for wearable electronics. Additionally, multifunctional electronic operations such as photoinduced heating, temperature sensing, and motion sensing are possible, and this study may pave the way for the development of a new class of smart wearable electronics for healthcare and soft robotics.