4D Multimaterial Printing of Programmable and Selective Light‐Activated Shape‐Memory Structures with Embedded Gold Nanoparticles

Abstract

4D printing is based on 3D printing of objects that can change their shape upon a proper triggering. Here, a novel approach is reported for fabricating programmable 3D printed objects composed of shape‐memory polymers (SMPs) that are activated by light. The light activation of the movement and shape morphing are based on combining gold nanoparticles (AuNPs) as photothermal converters with acrylate‐based printing compositions that form an SMP with tunable transition temperatures. The shape change of the printed objects is triggered by remote irradiation with a low‐cost LED light at a wavelength specific to the surface plasmon resonance of the embedded AuNPs. The light is converted to heat which enables the shape transition when the temperature reaches the Tg of the polymer. Excellent SMP properties are achieved with shape fixity and recovery ratios over 95%. This material composition and triggering approach enable fabricating programmable light‐activated 3D printed structures with a dual transition while tuning the concentration. Furthermore, numerical simulations performed by finite‐element analysis result in the excellent prediction of the shape‐memory recovery. The presented approach can be applied in remotely controlling morphing, mainly for applications in the fields of actuators and soft robotics.

Digital Light 3D Printed Bioresorbable and NIR‐Responsive Devices with Photothermal and Shape‐Memory Functions

“…Then, the sample was exposed to NIR light (808‐nm laser) for 1 min and the unrecovered angle ( θ unrecovered ) was recorded. [ 17 ] In case a sample flipped to the other side during heating, it was manually brought back to its initial position. For a control sample, instead of repeated NIR light exposure, sample was left for 2 days at room temperature.…”

“…202200907 One of the key advantages of DLP lies in the versatility of printable resins, which allows tuning the mechanical properties from tough and rigid to elastomers resembling soft tissues, as well as the incorporation of stimuli responsiveness to enable 4D printing. [14][15][16][17] Recently, biodegradable medical devices manufactured by DLP have been reported, [8,18] thus eliminating the need for additional interventions to extract them from the body. [19][20][21][22] With the increasing range of materials printable by DLP, the technology is now mature to fulfill the growing demand for 3D printed personalized devices with therapeutic functions.…”

“…[33,36,[39][40][41] When mixed with thermally-induced shape-memory polymers, these nanoparticles offer the opportunity for the 4D printing of "smart" devices that could be easily deployed and later expanded by NIR light. [17,[42][43][44][45][46] Shape-memory devices can be deformed above their transition temperature (e.g., glass transition temperature or melting point) to achieve a new shape that is then preserved by cooling the object below the transition temperature, which is referred to as the programming step. When the object is heated again above its transition point, it recovers to its original 3D printed shape.…”

Soft Optomechanical Systems for Sensing, Modulation, and Actuation

“…[194] Also, a 3D-printing approach was developed to fabricate light-driven actuators based on shape-memory polymers with phase transitions triggered by embedded AuNPs as photothermal agent. [195] Fe or iron-oxide (FeO) powder was used in combination with a LCN to develop a dual optical-magnetic actuator (Figure 8b), [196,197] which was applied to develop a mechanical gripper that could be transported and rotated by a magnet and actuated using blue light. Dyes and graphene have also been used as photothermal agents to drive phase transitions in LC.…”

A Bioinspired Plasmonic Nanocomposite Actuator Sunlight‐Driven by a Photothermal‐Hygroscopic Effect for Sustainable Soft Robotics

“…Differently, light‐responsive actuators have been mostly studied by focusing on specific material properties as well as trans–cis isomerization (e.g., in azobenzene‐based molecules) [ 16 ] or photothermal conversion [ 17,18 ] (e.g., in MXenes, [ 19–22 ] Graphene, [ 23–25 ] Carbon Nanotubes (CNTs) [ 26 ] and Metal Nanoparticles (MNPs). [ 27–32 ]…”