Soft electronics
Soft electronics necessitate substrates or supports with profound strain-stiffening properties to uphold functionality under mechanical deformation. Strain-stiffening materials have emerged to tackle the challenge of safeguarding electronics from high-peak strains that may arise during deformation.
One method involves depositing a thin film or mesh of a high-modulus material onto a pre-strained compliant substrate, leading to a wrinkled geometry upon release of the pre-strain. Another strategy entails employing a layered architectural composite design achieved by bonding a patterned thin film of stiff material to an elastomeric substrate. These designs offer a low elastic modulus at small strains and a high tangent modulus at large strains, resulting in a high ratio of tangent-to-elastic moduli, which corresponds to sharp nonlinear stress-strain behavior. Nonetheless, the ongoing challenge lies in fabricating thinner materials that effectively address critical issues such as breathability (high porosity), conformability (high flexibility and bendability), and lightweight.
Our work draws inspiration from the distinctive nonlinear strain-stiffening properties observed in curved and crimped microstructures found in biological soft tissues like the human dermis. Through a sequential fabrication process integrating electrospinning and electrowriting, we develope significantly enhanced strain-stiffening structural nonwoven mats that demonstrate competitive performance compared to existing strain-stiffening (bio)synthetic materials. Thus, our research contributes to the advancement of biomimetic electrospun load-bearing strain-stiffening materials for on-skin and wearable systems, addressing shortcomings often encountered with traditional materials in meeting the basic somatosensory requirements.