All‐Around Universal and Photoelastic Self‐Healing Elastomer with High Toughness and Resilience (Adv. Sci. 24/2021)

Abstract

Self‐Healing Elastomers Soft electronics seek all‐around high mechanical performance universal self‐healing elastomers. In article number 2103235, Jarkko Tolvanen and co‐workers report design strategy to achieve tough and resilient universal self‐healing elastomer. The resilin‐inspired bimodal siloxane‐based elastomer benefits from combination of soft and hard phases. The cover displays existing phase‐separated morphology during shape recovery captured by optical microscopy.

Stretchable Self‐Healing Plastic Polyurethane with Super‐High Modulus by Local Phase‐Lock Strategy

“…a) Comparison of the mechanical properties of self‐healing material reported in this work and those in related references, [20, 28,42–48 ] cyclic tensile curves at different maximum strains of b) PU‐ 2 Im‐Ni 0.25 , c) PU‐ 2 Im‐Ni 0.5 , d) PU‐ 4 Im‐Ni 0.25 , e) PU‐ 4 Im‐Ni 0.5 , and f) the comparison of damping efficiency of the complexes.…”

Ultraelastic and High‐Conductivity Multiphase Conductor with Universally Autonomous Self‐Healing

“…In our previous work, we optimized tensile and self‐healing properties of electrically nonconductive siloxane‐based elastomer (Figure S1, Supporting Information) with bimodal polymer chain length distribution, heterogeneity, and macroscale phase separation. [ 13 ] By forming a multicomponent blend, where kinetics of phase separation and structure formation could be further controlled, it would be possible to introduce electrical conductivity while considerably further improve the excellent tensile and self‐healing properties of the supramolecular elastomer. This would be possible, for example, with the use of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) which is one most well‐known π ‐conjugated polymers due to numerous applications in soft electronics.…”

“…The flaw insensitivity was absent in the electrically nonconductive elastomer reported in our previous work. [ 13 ] Remarkably, the multiphase conductor could be stretched to a similar degree regardless of the size and shape of the crack. The flaw insensitive behavior is not typical for elastomers, or stretchable conductors, especially as larger cracks easily propagate in single elastomeric networks (Figure S26, Supporting Information).…”

“…Hence, existing microlevel variations and high free volume would result in a faster rebonding and macroscopic network rearrangements through the hydrophilic and the hydrophobic interactions. The heterogeneity and large domain sizes present in the material would restrict the nonreversible flow in the elastomeric network even at extremely large deformations, [ 13 ] thus allow entropic elasticity (as shown in Figure 1c).…”

“…Absence of band intensities for the Si:OB dative bonded absorption peak intensity (at wavenumber of 1340 cm −1 ), nonhydrogen (at 3700 cm −1 ), and intermolecular hydrogen bonded bands (at 3290 cm −1 ) indicate that the condensation reaction was complete. [ 13 ] Stretching vibrations of thiophene rings were found at 670 cm −1 (for CSC bond), 1390 cm −1 , and 1550 cm −1 . Stretching vibrations for sulfonyl groups were not visible due to strong band intensity of Si(CH 3 ) 2 (at 1020–1090 cm −1 ) and Si(CH 3 ) 2 OSi(CH 3 ) 2 (at 1260 cm −1 ).…”