Abstract: The pattern complexity and functional value of wrinkled structures can be substantially increased by fabricating the wrinkles on pre-patterned quasi-planar substrates instead of flat substrates. This disclosure presents the methods for fabricating pre-patterned polymeric surfaces that can be subsequently used as the substrates during manufacture of complex wrinkled structures. Pre-patterned substrates are generated by imprinting the pre-patterns onto the substrates during the curing process. Suitability for post-curing use in fabrication of wrinkles is ensured by (i) delayed imprinting that occurs close to but before the gelation point and (ii) gradual alignment of pre-patterns to the direction of stretch that is applied later during manufacture of wrinkled structures.

Abstract: The range of stretch-tunability of sinusoidal wrinkled surfaces that are obtained by compression of supported thin films is limited by the emergence of a period-doubled mode at high compressive strains. This disclosure presents a method to suppress the emergence of the period-doubled mode at high strains. This is achieved by compressing pre-patterned supported thin films, wherein the pre-patterns are substantially similar to the natural pattern of the supported thin film system. As compared to flat thin film systems, pre-patterned thin film systems exhibit period doubling behavior at a higher compressive strain. The onset strain for emergence of period-doubling is tuned by altering the amplitude of the pre-patterns.

Abstract: Wrinkling of supported thin films is a strain-driven phenomenon that enables scalable and low-cost fabrication of periodic micro and nano scale structures. The morphology of wrinkles depends on both the magnitude and the nature of compressive strains that are applied to the thin film. This disclosure presents the methods to fabricate asymmetric 2-D wrinkled structures using biaxial compressive strains. The method relies on the dependence of wrinkle morphology on both strains and strain paths to generate asymmetric 2D wrinkles. Asymmetry is achieved by deliberately traversing the system through a strain state that creates cracks along a preferential direction. Fabricated patterns include non-uniform zigzag wrinkles that demonstrate period doubling only along one direction.

Abstract: Wrinkling of thin films is a strain-driven process that enables scalable and low-cost fabrication of periodic micro and nano scale patterns. However, real-world application is limited by the inability of current tools to provide the means for applying large, accurate, and non-equal biaxial strains via a device that can fit within the vacuum chambers that are required for thin film deposition/growth during wrinkling. The present biaxial tensile stage is a compact system that enables one to apply large and accurate non-equal biaxial strains to elastomeric films. It consists of (i) fixtures to clamp and hold films onto the stage, (ii) linear bearings for motion guidance, (iii) integrated actuators for real-time stretch control, (iv) base with kinematic coupling for registration to a metrology system, and (v) the structural frame.

Abstract: The pattern complexity and functional value of wrinkled structures can be substantially increased by fabricating the wrinkles on pre-patterned quasi-planar substrates instead of flat substrates. This disclosure presents the methods for fabricating pre-patterned polymeric surfaces that can be subsequently used as the substrates during manufacture of complex wrinkled structures. Pre-patterned substrates are generated by imprinting the pre-patterns onto the substrates during the curing process. Suitability for post-curing use in fabrication of wrinkles is ensured by (i) delayed imprinting that occurs close to but before the gelation point and (ii) gradual alignment of pre-patterns to the direction of stretch that is applied later during manufacture of wrinkled structures.

Abstract: Wrinkling of thin films is a strain-driven process that enables scalable and low-cost fabrication of periodic micro and nano scale patterns. However, real-world application is limited by the inability of current tools to provide the means for applying large, accurate, and non-equal biaxial strains via a device that can fit within the vacuum chambers that are required for thin film deposition/growth during wrinkling. The present biaxial tensile stage is a compact system that enables one to apply large and accurate non-equal biaxial strains to elastomeric films. It consists of (i) fixtures to clamp and hold films onto the stage, (ii) linear bearings for motion guidance, (iii) integrated actuators for real-time stretch control, (iv) base with kinematic coupling for registration to a metrology system, and (v) the structural frame.

Abstract: This invention relates to the low-cost manufacture of a tunable physical topographic pattern and more particularly to the manufacture of micro and nano scale hierarchical periodic wrinkle patterns that are generated upon compression of supported thin films. Disclosed herein is (i) a composite material with tunable hierarchical wrinkle patterns, wherein the composite material comprises a stretched and pre-patterned base layer and a thin film that is conformally attached to the pre-patterned surface of the base layer, (ii) a method of fabricating the pre-patterned base via pattern replication, and (iii) a method of fabricating tunable hierarchical wrinkle patterns, wherein the pattern can be deterministically switched across the hierarchical and non-hierarchical states via strain control.

Abstract: Passive stamp alignment system. The system includes a stamp supported by a stamp holder resting on three balls affixed to a top platform. A bottom platform supports a substrate to be aligned with the stamp. Means are provided for moving either the top or the bottom platform and holding the other platform stationary so as to contact the substrate with the stamp whereby the stamp holder is lifted away from each of the balls in sequence resulting in alignment of the stamp and the substrate parallel to each other.

Abstract: Passive stamp alignment system. The system includes a stamp supported by a stamp holder resting on three balls affixed to a top platform. A bottom platform supports a substrate to be aligned with the stamp. Means are provided for moving either the top or the bottom platform and holding the other platform stationary so as to contact the substrate with the stamp whereby the stamp holder is lifted away from each of the balls in sequence resulting in alignment of the stamp and the substrate parallel to each other.