Flow Casting Soft Shells with Geometrical Complexity and Multifunctionality

Abstract

Soft shells are ubiquitous in soft devices, e.g., soft robots, wearable sensors, and soft medial replicas. However, previous widely accepted methods, such as mold casting, dip coating, and additive manufacturing, are limited to thick shells due to the mold assembly and the large friction during demolding, long processing time for mold dissolution, and poor scalability, respectively. Here, a facile, robust, and scalable manufacturing technique, named flow casting, to create soft shells with complex geometries and multifunctionalities is proposed. The method involves a flow‐governed layer casting process and a peel‐dominated demolding process. A one‐dimensional soft shell is first made with controllable thicknesses (100–400 µm) and fabricated various soft shells of intricate geometries, including three‐branched, circular‐shaped, and exquisite microstructures such as papillae and microgrooves on curved surfaces, with the resolution of feature sizes on the order of 100 µm. Furthermore, the versatility of this method is demonstrated with a 3D vascular phantom model for a magnetic robot transporting, microstructured cubic sleeves for enhancing the grasping ability of rigid grippers, and a stretchable optical waveguide capable of color changing by external mechanical stimuli.

Soft Optical Waveguides for Biomedical Applications, Wearable Devices, and Soft Robotics: A Review

“…For example, compared to single-variable sensing, combination of wavelength (color) and intensity sensing is capable of distinguishing complex mechanical deformation. [72,100] These advancements in sensing fusion provide more comprehensive and accurate physiological information for health monitoring and disease diagnosis.…”

Innervation of Sensing Microchannels for Three‐Dimensional Stimuli Perception

“…[25][26][27] However, this resistive sensor lacks the sensibility for complex external stimuli, including shearing and twisting, and force direction recognition due to their 2D patterns. Although efforts, such as introducing a rigid part [26] and configuration design, [28,29] have been made for shear force and force direction recognition, the flat ge- ometries are unable to attach to uneven surfaces conformally. Moreover, embedded soft sensors into soft robotics have presented a potential solution to proprioception.…”