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A simple and facile processing strategy to enhance the thermomechanical properties of sulfur-rich polymers has been reported.

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. The height of the constructed micropillar decreases in the case of small microcavities or high viscosity resin. In addition, the height of the micropillar arrays could be arbitrarily patterned by applying a masking technique. We believe that this cost-effective technique can be applied to metasurfaces for manipulation of electromagnetic signal or in biomedical applications including cell-culture and stem-cell differentiation.

The jumping motion is adapted by Earth’s creatures to achieve rapid maneuverability and energy-efficient hurdling over uneven terrains or large obstacles. Herein, the continuous photomechanical jumping of polymer monoliths with on-demand height and angle programmability is reported. Upon exposure to actinic light, self-assembled spring-like molecular geometry of azobenzene-functionalized liquid crystalline polymers provide on-demand jumping via snap-through of non-isometric structures. The finite element method simulation quantitatively describes stress–strain responsivity of the experimental jumping. Remarkably, the maximum jumping height reaches 15.5 body length (BL) with the maximum instantaneous velocity of 880 BL s−1. We demonstrate programmable jumping height and angle by varying macroscopic geometry and light intensity profile. Finally, four continuous and directional jumping sequences are demonstrated within 5 s to overcome an obstacle.

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

Triboelectric nanogenerators (TENGs) are eco-friendly energy-harvesting systems that produce electrical energy from disordered mechanical energy. To enhance the triboelectric performances of TENGs, many researchers have conducted in-depth studies of the polymer materials utilized in TENGs, so numerous studies have been reported on the relationship between their material properties and their energy-harvesting capabilities. Triboelectric performance depends on the electrical properties of the materials used, such as their electron affinities and dielectric constants. Representative examples of positive and negative tribomaterials include PA6, PEO, PVDF, and fluorinated sulfur copolymers, respectively. This article introduces the relationship among the compositions, structures, triboelectric performances of the polymer materials, and composites used in TENGs and summarizes the representative polymer materials applied in the latest TENGs.

The effects of corn-starch content and high-energy ball-milling time on the microstructure and electrical properties of porous Y-doped (Ba, Sr)TiO3 samples were investigated. All the (Ba, Sr)TiO3 samples at room temperature crystallized in the tetragonal structure and the crystal structure was independent of the corn-starch content and ball-milling time. We found that the corn-starch additive and the ball-milling time affected the microstructure and the electrical properties. The (Ba, Sr)TiO3 samples exhibited a large PTCR jump (>105) due to the high porosity. The PTCR jump of the samples increased with increasing corn-starch content, while it decreased with increasing ball-milling time. In addition, the resistivity increased with increasing corn-starch content, while it decreased with increasing ball-milling time.

AlN based machinable ceramics containing hBN were prepared by economical pressureless sintering at 1800 °C for 2 h in a nitrogen gas atmosphere. The effects of hBN content on microstructure, mechanical properties and machinability were investigated. The relative density of sintered compacts decreased with increasing hBN content. The four-point flexural strength of 340 MPa for monolithic AlN also decreased to about 120 MPa by the addition of 20 vol% hBN, mainly due to increased porosity. With increasing hBN content, AlN–hBN based ceramic composites revealed increased crack deflection. The Vickers indentation crack paths in specimens were sinusoidal indicating crack bridging and pull-outs of composite grains during crack propagation. During end-milling and microdrilling processes for AlN ceramic composites with more than 10 vol% hBN, measured feed and thrust forces decreased with increasing hBN content, demonstrating a good machinability of the composites.