Spatially patterned stiffness variation in a light-triggered jumper for symmetry breaking and high snap-through efficiency.

The nonlinear strain response of soft material-based snap-through systems enables amplified and accelerated force output. However, efficiency of snap-through energy release is challenging to improve because of the inherent trade-off between initial curvature and stiffness. Here, spatial programming of stiffness variation in the azobenzene-functionalized liquid-crystalline polymer (Azo-LCP) addresses this limitation and achieves efficient photomechanical jumping.

Closed-Loop and Sustainable 4D Printing of Multi-Stimuli-Responsive Sulfur-Rich Polymer Composites for Autonomous Task Execution.

Shape-programmable polymer networks derived from waste elemental sulfur hold great potential for diverse applications such as 4D printing and soft robotics. However, their crosslinked nature makes it challenging to 3D print complex geometry for soft robots. Herein, a closed-loop 4D printing strategy is reported of poly(phenylene polysulfide) networks (PSNs) and their magnetic particle composites (MPSNs) to fabricate multi-functional soft robots with programmable shape-morphing capabilities.

Light-Fueled In-Operando Shape Reconfiguration, Fixation, and Recovery of Magnetically Actuated Microtextured Covalent Adaptable Networks.

Covalent adaptable networks (CANs) enable reprocessability via dynamic bond exchange above their topology freezing transition temperature (T) despite chemical crosslinks. However, conventional CANs often exhibit insufficient viscosity reduction upon heating, necessitating extensive application of heat and pressure through direct contact for processing. In this study, a disulfide-bonded CAN is introduced to facilitate UV-assisted processing at room temperature, in addition to conventional thermal processing above T.

Photopolymer Resins from Sulfenyl Chloride Commodity Chemicals for Plastic Optics, Photopatterning and 3D-Printing.

The development of a low-cost photopolymer resin to fabricate optical glass of high refractive index for plastic optics is reported. This new free radically polymerizable photopolymer resin, termed, disulfide methacrylate resin (DSMR) is synthesized by the direct addition of allyl methacrylate to a commodity sulfur petrochemical, sulfur monochloride (SCl). The rapid rates of free radical photopolymerization confer significant advantages in preparing high-quality, bulk optical glass.

Programming Anisotropic Functionality of 3D Microdenticles by Staggered-Overlapped and Multilayered Microarchitectures.

Natural sharkskin features staggered-overlapped and multilayered architectures of riblet-textured anisotropic microdenticles, exhibiting drag reduction and providing a flexible yet strong armor. However, the artificial fabrication of three-dimensional (3D) sharkskin with these unique functionalities and mechanical integrity is a challenge using conventional techniques. In this study, it is reported on the facile microfabrication of multilayered 3D sharkskin through the magnetic actuation of polymeric composites and subsequent chemical shape fixation by casting thin polymeric films.

Steerable and Agile Light-Fueled Rolling Locomotors by Curvature-Engineered Torsional Torque.

On-demand photo-steerable amphibious rolling motions are generated by the structural engineering of monolithic soft locomotors. Photo-morphogenesis of azobenzene-functionalized liquid crystal polymer networks (azo-LCNs) is designed from spiral ribbon to helicoid helices, employing a 270° super-twisted nematic molecular geometry with aspect ratio variations of azo-LCN strips. Unlike the intermittent and biased rolling of spiral ribbon azo-LCNs with center-of-mass shifting, the axial torsional torque of helicoid azo-LCNs enables continuous and straight rolling at high rotation rates (≈720 rpm).

Highly Sensitive and Cost-Effective Polymeric-Sulfur-Based Mid-Wavelength Infrared Linear Polarizers with Tailored Fabry-Pérot Resonance.

Inverse-vulcanized polymeric sulfur has received considerable attention for application in waste-based infrared (IR) polarizers with high polarization sensitivities, owing to its high transmittance in the IR region and thermal processability. However, there have been few reports on highly sensitive polymeric sulfur-based polarizers by replication of pre-simulated dimensions to achieve a high transmission of the transverse magnetic field (T ) and extinction ratio (ER). Herein, a 400-nanometer-pitch mid-wavelength infrared bilayer linear polarizer with self-aligned metal gratings is introduced on polymeric sulfur gratings integrated with a spacer layer (SM-polarizer).

Height-Tunable Replica Molding Using Viscous Polymeric Resins.

Replica molding is one of the most common and low-cost methods for constructing microstructures for various applications, including dry adhesives, optics, tissue engineering, and strain sensors. However, replica molding provides only a single-height microstructure from a mold and master molds produced by an expensive photolithography process are required to prepare microstructures with different heights. Herein, we present a strategy to control the height of micropillars from the same mold by varying the cavity size of the micromold and the viscosity of the photocurable polyimide resin.