DLP 4D Printing of Multi‐Responsive Bilayered Structures

Abstract

Advances in soft robotics strongly rely on the development and manufacturing of new responsive soft materials. In particular, light‐based 3D printing techniques, and especially, digital light processing (DLP), offer a versatile platform for the fast manufacturing of complex 3D/4D structures with a high spatial resolution. In this work, DLP all‐printed bilayered structures exhibiting reversible and multi‐responsive behavior are presented for the first time. For this purpose, liquid crystal elastomers (LCEs) are used as active layers and combined with a printable non‐responsive elastomer acting as a passive layer. Furthermore, selective light response is incorporated by embedding various organic dyes absorbing light at different regimes in the active layers. An in‐depth characterization of the single materials and printed bilayers demonstrates a reversible and selective response. Last, the versatility of the approach is shown by DLP printing a bilayered complex 3D structure consisting of four different materials (a passive and three different LCE active materials), which exhibit different actuation patterns when irradiated with different wavelengths of light.

4D Printing of Shape-Morphing Liquid Crystal Elastomers

“…Mainik et al reported a general method for the first time to fabricate a DLP-printed multi-responsive LCE actuator based on a double-layer structure that exhibited reversible and complex actuation modes. 141 These structures are composed of an active layer made of LCE and a passivation layer made of a printable non-responsive elastomer. Multiwavelength responsiveness is easily achieved by incorporating diverse organic dyes that exhibit absorption in different regions, ranging from visible blue to the near-infrared spectral range.…”

“…Reproduced with permission. Copyright 2023, John Wiley & Sons, Inc. (f) Multi-wavelength responsive LCE composite actuators . Reproduced with permission.…”

“…Due to the high spatial resolution, DLP has recently shown advantages in 4D printing of complex LCE structures. Mainik et al reported a general method for the first time to fabricate a DLP-printed multi-responsive LCE actuator based on a double-layer structure that exhibited reversible and complex actuation modes . These structures are composed of an active layer made of LCE and a passivation layer made of a printable non-responsive elastomer.…”

Solvent-triggered shape change in gradient-based 4D printed bilayers: case study on semi-crystalline polymer networks

“…In this panorama, 4D printing represents a powerful and flexible technology to manufacture actuators with complex architectures and enhanced shape-morphing over time (the 4th dimension) after fabrication. 1,4 In particular, 4D printed bilayers are among the simplest and most investigated actuation systems, 5 where their shape transformation is generally an out-of-plane bending. Narrowing the focus to extrusion-based 4D printing, that offers several advantages over other printing techniques ( e.g.…”