Photopolymerization of Pollen Based Biosourced Composites and Applications in 3D and 4D Printing

Pollen have the potential to be effective plant-based biorenewable reinforcing fillers for polymers due to their chemical stability and unique micro- or nano-structured surfaces. Pollen-polymer composites can form the basis for a new class of light-weight and sustainable materials if compatible polymer-filler systems can be engineered through photopolymerization, but this idea is previously unexplored. The first demonstration of photopolymerization and 3D printing with the incorporation of pine pollen as filler in poly(ethylene glycol) diacrylate are presented. The filler properties affecting the related depth of cure and the mechanical, thermal, and functional properties are examined in detail. In addition, the lithography technique is applied to the photocomposites for the production of 3D patterns. 4D printing behavior is also possible through the water swelling and dehydration induced actuation of the 3D printed composites with spatial resolution features. This work is expected to provide a new way to a field for photopolymerization reactions in natural material-resin composites and thereby to expand potential applications in 3D and 4D printing.