Biomimetic Thermal-sensitive Multi-transform Actuator

Abstract

Controllable and miniaturised mechanical actuation is one of the main challenges facing various emerging technologies, such as soft robotics, drug delivery systems, and microfluidics. Here we introduce a simple method for constructing actuating devices with programmable complex motions. Thermally responsive hydrogels based on poly( N -isopropylacrylamide) (PNIPAM) and its functionalized derivatives (f-PNIPAM) were used to control the lower critical solution temperature (LCST) or the temperature at which the gel volume changes. Techniques for ultra-violet crosslinking the monomer solutions were developed to generate gel sheets with controllable crosslink density gradients that allowed bending actuation to specified curvatures by heating through the LCST. Simple molding processes were then used to construct multi-transform devices with complex shape changes, including a bioinspired artificial flower that shows blossoming and reverse blossoming with a change in temperature.

Sunlight-Activated Phase Transformation in Carbon Dot-Hydrogel Facilitates Water Purification and Optical Switching

“…Overall, the greater C-dot concentration was responsible for modulation of the swelling property and LCST of PNIAPM . Previous studies reported a similar effect of PNIPAM phase transitions upon incorporation of guest species within the polymer matrix. , …”

“…44 Previous studies reported a similar effect of PNIPAM phase transitions upon incorporation of guest species within the polymer matrix. 45,46 3. mg/mL) in comparison with a bare CMC−PNIPAM gel not containing C-dots. Indeed, the data in Figure 4 demonstrate that inclusion of the C-dots in the CMC−PNIPAM hydrogel yielded a superior desalination performance.…”

Materials, Actuators, and Sensors for Soft Bioinspired Robots

“…Its structure is well defined, and its tunable LCST is close to human body temperature. [34,35] Figure 4B shows a thermoresponsive hydrogel with a gradient pore structure expanding and contracting in response to changes in temperature. [84] The usage of hydrogel is highly preferable in applications where biocompatibility is essential.…”

“…Using this technique, they fabricated a bioinspired artificial flower with two distinct LCSTs (48° and 60.8°) (Figure 11E,F). [35] Figure 11. Thermoresponsive actuators.…”

“…Presently, a diversified list of materials has been used in the development of soft robotic systems. This section will cover some of the latest advancements in the last 4 years in the area of material selection and composition for the design and development of soft bioinspired actuators and sensors.During the past 4 years, researchers have produced soft bioinspired actuators and sensors using biological material such as muscle tissue, [23,24] and plant fibers; [25] carbon-based materials such as graphite and graphene oxide (GO) [26][27][28][29][30][31] and carbon nanotubes (CN); [32,33] hydrogel materials such as poly(Nisopropylacrylamide) (PNIPAM), [34,35] liquid crystal elastomers (LCE), [36] dielectric elastomers (DE), [37] and ionic polymermetal composites (IPMC). [38] An overview of these materials (Figure 1), along with their underlying mechanisms, are discussed below.Biological systems can perform complex tasks with high compliance levels.…”