Search for: All records

Multimaterial additive manufacturing has important applications in various emerging fields. However, it is very challenging due to material and printing technology limitations. Here, we present a resin design strategy that can be used for single-vat single-cure grayscale digital light processing (g-DLP) 3D printing where light intensity can locally control the conversion of monomers to form from a highly stretchable soft organogel to a stiff thermoset within in a single layer of printing. The high modulus contrast and high stretchability can be realized simultaneously in a monolithic structure at a high printing speed (z-direction height 1 mm/min). We further demonstrate that the capability can enable previously unachievable or hard-to-achieve 3D printed structures for biomimetic designs, inflatable soft robots and actuators, and soft stretchable electronics. This resin design strategy thus provides a material solution in multimaterial additive manufacture for a variety of emerging applications.

Pattern switching (or transformation) widely exists in the activities of various creatures and plays an important role in designing adaptive structures in modern materials. Utilizing the glass transition behavior in amorphous polymers, thermomechanically triggered two‐stage pattern switching of 2D lattices is achieved, where components made of an amorphous polymer and a flexible elastomer are interconnected in predesigned layouts. Upon loading at room temperature, the elastomer is far more flexible than the amorphous polymer and the lattice switches into one pattern. With temperature increasing, the modulus of the amorphous polymer decreases due to glass transition. Under the proper choice of amorphous polymer whose storage modulus can decrease to below the modulus of the elastomer, a change in the relative stiffness can be achieved and can switch the overall pattern from one to another while maintaining the external load. Both the experimental and computational studies are carried out to investigate the switching mechanism. Several periodic structures are fabricated to demonstrate several switched patterns. Particularly, a proof‐of‐concept smart window design is fabricated to explore the potential engineering applications.