Fluorine-Based Elastomer Revolutionizes Flexible Electronics

This work of Professor Zhengwei You and Professor Junfen Sun from the College of Materials Science and Engineering, Donghua University, China, have been published by Science Bulletin. There is usually a trade−off between high mechanical strength and dynamic self−healing because the mechanisms of these properties are mutually exclusive. Herein, this team design and fabricate a fluorinated phenolic polyurethane (FPPU) elastomer based on octafluoro−4,4'−biphenol to overcome this challenge. This fluorine−based motif not only tunes interchain interactions through π−π stacking between aromatic rings and free−volume among polymer chains but also improves the reversibility of phenol−carbamate bonds via electron−withdrawing effect of fluorine atoms. The developed FPPU elastomer shows the highest recorded puncture energy (648.0 mJ), high tensile strength (27.0 MPa), as well as excellent self−healing efficiency (92.3%), along with low surface energy (50.9 MJ m⁻²), notch−insensitivity, and reprocessability compared with non−fluorinated counterpart biphenolic polyurethane (BPPU) elastomer. Taking advantage of the above−mentioned merits of FPPU elastomer, this team prepare an anti−fouling triboelectric nanogenerator (TENG) with a self−healable, and reprocessable elastic substrate. Benefiting from stronger electron affinity of fluorine atoms than hydrogen atoms, this electronic device exhibits ultrahigh peak open−circuit voltage of 302.3 V compared to the TENG fabricated from BPPU elastomer. Furthermore, a healable and stretchable conductive composite is prepared. This research provides a distinct and general pathway toward constructing high−performance elastomers and will enable a series of new applications.