Multi-objective optimization for shrinkage, mechanical, and shape-memory behavior in 4D printed polymer composites

In the context of 4D printing, the term "fourth dimension" pertains to the capacity of materials to change their shape or form once they have been manufactured. This characteristic enables them to possess enhanced functional capabilities and enables the creation of applications that prioritize performance. Stimulus-responsive materials like shape memory polymers provide great opportunities to be used in 4D printing for a wide range of applications. Using polylactic acid (PLA) and bioactive glass (BG), this study demonstrates the developed material's potential for processing and experimentation for shape memory properties and 4D printing. Expanding our approach, a multi-objective optimization was done to minimize shrinkage and maximize strength along with shape recovery for 4D printed shape memory polymer composites (SMPCs) with the help of the central composite design (CCD) approach commonly referred to as response surface methodology (RSM). The model was validated by conducting confirmation tests using the best possible combination of parameters for the process, as determined utilizing the genetic algorithm multi-objective optimization method. In the end, different structures were developed by utilizing 4D printing at optimum parameters and the shape-changing behavior was recorded in the 4D printed parts by applying a thermal stimulus.