Tacky Elastomers to Enable Tear‐Resistant and Autonomous Self‐Healing Semiconductor Composites

Abstract

Mechanical failure of π-conjugated polymer thin films is unavoidable under cyclic loading conditions, due to intrinsic defects and poor resistance to crack propagation. Here, the first tear-resistant and roomtemperature self-healable semiconducting composites is presented, consisting of conjugated polymers and butyl rubber elastomers. This new composite displays both record-low elastic modulus (< 1 MPa) and ultra-high deformability with fracture strain above 800%. More importantly, failure behavior is not sensitive to precut notches under deformation. Autonomous self-healing at room temperature, both mechanical and electronic, is demonstrated through physical contact of two separate films. The composite film also shows device stability in the ambient environment over five months due to muchimproved barrier property to both oxygen and water. Butyl rubber is broadly applicable to various Ptype and N-type semiconducting polymers for fabricating self-healable electronics to provide new resilient electronics that mimic the tear resistance and healable property of human skin.

A design strategy for high mobility stretchable polymer semiconductors

“…2). So far, few such polymers have been reported 50 . When naphthalene diimide (4,9-dibromo-2,7-bis (2-decyltetradecyl)benzo[lmn] [3,8]phenanthroline-1,3,6,8 (2H,7H)-tetraone ((NDI)) was used as an acceptor unit, our newly developed NDI-8TVT exhibited the crack onset strain of 93%, which was a 30-fold improvement compared with NDI-10TVT.…”

Molecular Origin of Strain‐Induced Chain Alignment in PDPP‐Based Semiconducting Polymeric Thin Films

“…All four polymers were spun cast on the silicon substrate to fabricate thin films with a thickness around 100 nm, followed by tensile testing on the water surface using a previously reported pseudofree-standing tensile tester, or film-on-water (FOW) tester. [55][56][57][58][59] Figure 1b plotted true stress (σ T ) -true strain (ε T ) curves of the four polymers, with optical images of PDPPT-C2C8C10 thin films at two strains highlighted to show the deformation behavior. It is also observed that polymers with shorter sidechain lengths are easier to deform along the width direction, i.e., a more evident Poisson effect (Figure 1b; Videos S1-S4, Supporting Information).…”

Direct Observation of Confinement Effects of Semiconducting Polymers in Polymer Blend Electronic Systems

“…Polymer blend electronics, which are based on a composite of a semiconducting polymer (SP) and insulating polymer (IP), have advanced rapidly and garnered significant interest because of their attractive potential in various applications such as, transparent electronic, [ 1 , 2 , 3 ] stretchable/flexible electronic, [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] and self‐healing/biodegradable electronic [ 12 , 13 , 14 , 15 , 16 ] devices. The key merit of the polymer blend approach is the fact that this approach enables integration of specific physical properties of SPs and IPs without sophisticated material synthesis being required, while maintaining the semiconducting properties of SPs.…”

“…The key merit of the polymer blend approach is the fact that this approach enables integration of specific physical properties of SPs and IPs without sophisticated material synthesis being required, while maintaining the semiconducting properties of SPs. [ 17 , 18 , 19 ] Pioneering studies on SP:IP blends have demonstrated that this simple blending method can achieve various beneficial functionalities, including patterning processability, [ 20 ] mechanical stretchability, [ 4 , 5 , 6 , 8 , 9 , 10 , 11 ] self‐healability, [ 12 , 13 ] air stability, [ 21 , 22 ] thermal stability, [ 23 ] and excellent optical transparency. [ 1 , 2 , 21 ] Furthermore, in addition to the studies exploring the integration of the physical properties, a few notable works have demonstrated that despite containing a significant amount of IPs, SP:IP blend systems exhibit charge carrier mobilities that are comparable or even superior to those of pure SPs, along with newly arising polymer blend characteristics.…”