# Tailoring the Shape‐Memory Performance of 2D and 3D Fabricated Semi‐Crystalline PCL Networks Via Optimal Crosslinking

## TL;DR

This study explores how photo-crosslinking parameters and fabrication methods affect the shape-memory performance of PCL networks in 2D and 3D.

## Contribution

The paper provides practical design guidelines for engineering PCL-based semi-crystalline structures with tunable properties.

## Key findings

- Crosslinking above PCL's melting temperature and using high UV intensity improves shape-memory performance.
- 3D printed samples have reduced shape-memory performance despite comparable thermal properties to 2D samples.
- Post-treatment with additional UV exposure enhances two-way shape-memory behavior.

## Abstract

Photo‐crosslinking is a fast and efficient approach to obtain chemically crosslinked semi‐crystalline networks featuring both one‐way and two‐way shape‐memory effect. However, the effect of photo‐crosslinking parameters and fabrication method on the physical, thermo‐mechanical, and shape‐memory properties of these networks still has to be investigated. This paper aims to fill this gap, specifically focusing on semi‐crystalline polycaprolactone (PCL) networks. In detail, the influence of key photo‐crosslinking parameters ‐crosslinking temperature and UV light intensity‐ as well as the fabrication method ‐2D vs. 3D‐ were investigated. As a general trend, crosslinking above the melting temperature of PCL and selecting a high UV light intensity yielded structures with superior performance, also displaying stress‐free shape‐memory behavior. Conversely, crosslinking below the crystallization temperature of PCL and selecting a low UV light intensity led to reduced performance and absence of stress‐free actuation. To address this limitation, a post‐treatment involving additional UV exposure was introduced, which significantly improved overall performance, particularly enhancing the two‐way shape‐memory behavior. Interestingly, although the 3D printed samples displayed thermal properties comparable to their 2D counterparts, their shape‐memory performance was significantly reduced. Overall, these findings provide practical design guidelines for engineering 2D and 3D PCL‐based semi‐crystalline structures with tunable physical, thermal, and shape‐memory properties.

This study investigates the impact of two key photo‐crosslinking parameters, namely the crosslinking temperature and the UV light intensity, as well as the effect of the fabrication method, i.e., 2D vs. 3D, on the physicochemical, thermal, mechanical, and shape‐memory properties of polycaprolactone (PCL)‐based semi‐crystalline polymer networks.