Abstract: An approach to achieve highly tunable adhesion using low pressure by inducing sidewall buckling in soft hollow pillars (SHPs). Dry adhesion of these SHPs can be changed by two orders of magnitude (up to 145×) using low activating pressure (˜?10 kPa or ˜20 kPa). Negative pressure triggers sidewall buckling while positive pressure induces sidewall bulging, both of which can significantly change stress distribution at the bottom surface to facilitate crack initiation and reduce adhesion therein. A single SHP can be activated by a micropump to manipulate various lightweight objects with different curvature and surface texture. An array of SHPs can realize selective pick-and-place of an array of objects. Minor modifications to the SHPs in terms of geometry and material (with or without cap, circular or noncircular cross section) can further enhance the adhesion tuning performance of these SHPs.

Abstract: A variety of polymeric composites with tunable mechanical stiffness and electrical conductivity are claimed herein. For example, the composite may have an elastomeric matrix, a plurality of tunable particles, and a plurality of conductive fibers embedded in the matrix. The composites may also be a tunable foam matrix and an elastomeric matrix. In some embodiments, the composites are a low melting point alloy (LMPA) foam infiltrated by an elastomer, whose stiffness can be tuned by more than two orders of magnitude through external heating. In other embodiments, the composite may be a conductive particle-fiber-matrix three-component composite capable of changing its elastic rigidity rapidly and reversibly when powered with electrical current.

Abstract: Disclosed herein are embodiments of methods that utilize dry adhesion tuning of a composite structure to adhere substrates. In some embodiments, the disclosed methods utilize dry adhesion between a composite structure and a substrate and further dynamically control the resulting dry adhesion strength through a heating step, which facilitates rigidity tuning of a core component of the composite structure and/or facilitates thermal control of the interface between the substrate and the composite structure. Also disclosed herein are array devices and other products comprising the disclosed composite structures.

Abstract: A variety of polymeric composites with tunable mechanical stiffness and electrical conductivity are claimed herein. For example, the composite may have an elastomeric matrix, a plurality of tunable particles, and a plurality of conductive fibers embedded in the matrix. The composites may also be a tunable foam matrix and an elastomeric matrix. In some embodiments, the composites are a low melting point alloy (LMPA) foam infiltrated by an elastomer, whose stiffness can be tuned by more than two orders of magnitude through external heating. In other embodiments, the composite may be a conductive particle-fiber-matrix three-component composite capable of changing its elastic rigidity rapidly and reversibly when powered with electrical current.

Abstract: Disclosed herein are embodiments of methods that utilize dry adhesion tuning of a composite structure to adhere substrates. In some embodiments, the disclosed methods utilize dry adhesion between a composite structure and a substrate and further dynamically control the resulting dry adhesion strength through a heating step, which facilitates rigidity tuning of a core component of the composite structure and/or facilitates thermal control of the interface between the substrate and the composite structure. Also disclosed herein are array devices and other products comprising the disclosed composite structures.

Abstract: Disclosed herein is a composite comprising a conductive elastomer and an isolating elastomer. When a current is passed through the conductive elastomer, its tensile modulus decreases as the elastomer heats from internal Joule heating, changing the rigidity of the composite. When the current is no longer present, the elastomer cools and the rigidity of the composite returns to its original state.

Abstract: Disclosed herein is a composite comprising a conductive elastomer and an isolating elastomer. When a current is passed through the conductive elastomer, its tensile modulus decreases as the elastomer heats from internal Joule heating, changing the rigidity of the composite. When the current is no longer present, the elastomer cools and the rigidity of the composite returns to its original state.