Recent advances in 3D printing has enabled integration of multiple materials with divergent properties through spatially patterning. While the spectrum of available materials affords large property variations, the interface between dissimilar materials is vulnerable to failure. The interface that forms between two materials is critical to the stability and function of a device. Hence, strategies are needed to predictably and precisely control integration. This talk explores integration of crosslinked polymers (hydrogels) for their widespread applications in 3D printing. The objectives were to establish a link between printing parameters and material properties to enable deterministic spatial control over integration via diffusion processes. By characterizing polymerization kinetics and mapping conversion to effective dose, it is possible to link printing parameters of light intensity and exposure time directly to conversion and ultimately to material properties of the printed resin. Applying this approach to grayscale exposures enabled spatial control over hydrogel mesh size, which then controls diffusion of the second material. Conversions from 13.5% to 100% of the stiff hydrogel led to variations in the hydrogel mesh size from 11.5 nm to 1.3 nm respectively. A low conversion of 13.5% afforded transport of the precursors of the second soft hydrogel, while a high conversion (100%) restricted transport and prevented integration. By precisely prescribing material properties, we demonstrate controlled integration of two heterogeneous materials of different stiffness with interfacial regions that range from 10s of microns to centimeters. Feasibility of this approach is finally demonstrated through integration of multiple materials and osteoblastic cells.
- Utilize predictive models to prescribe material properties as a function of the printing parameters
- Understand fundamental challenges in Stereolithography-based 3D printing and strategies to overcome them
- Employ new strategies of micro resolution 3D printing towards composites based biological scaffolds