FABRICATION OF SOLID POLYMERIC 3D SHAPES FROM PROGRAMMABLE FLAT HYDROGEL SHEETS

Abstract

Modern methods of fabricating three-dimensional (3D) objects include sheet metal forming, thermoforming, and additive manufacturing among others. These methods have their own advantages and disadvantages regarding scalability, customizability, and time efficiency. A promising approach is to program the growth (expansion and contraction) of hydrogel sheets to form 3D structures. The differential growth-induced 3D shaping approach has the advantages of traditional manufacturing (scalability) and additive manufacturing (customizability). The objective of this study is to create nanocomposite 3D structures that are stable in ambient environment using the growth-induced 3D shaping approach. This study determines the effect of silica nanoparticles in hydrogels on the shape forming capability to build 3D structures of silica nanocomposites. The drying process of nanocomposite hydrogels at the shrunk state leads to air-stable 3D structures. The mechanical properties of the resulting 3D structures are comparable to those of polymer structures fabricated by conventional additive manufacturing methods. The hardness and yield strength of the structures increase with the concentration of silica nanoparticles in them. Scanning electron microscopy shows an excellent surface finish of the fabricated 3D structures. This approach could open new routes for manufacturing 3D structures with customized design in a scalable way.