Journal of Composites Science

Liquid crystal elastomers (LCEs), as a class of smart materials, have attracted significant attention across soft robotics, biomedical engineering, and intelligent devices because of their unique capabilities to undergo large, reversible, and anisotropic deformations under external stimuli. Over the years, fabrication methods have advanced from conventional molding and thin-film processing to additive manufacturing, with 4D printing emerging as a transformative approach by enabling time-dependent, programmable shape transformations. Among the available methods, direct ink writing (DIW) and vat photopolymerization are most widely adopted, with ink chemistry, rheology, curing, and printing parameters directly governing mesogen alignment and actuation performance. Recent advances in LCE actuators have demonstrated diverse functionalities in soft robotics, including bending, crawling, gripping, and sequential actuation, while biomedical applications span adaptive tissue scaffolds, wearable sensors, and patient-specific implants. This review discusses the conceptual distinction between 3D and 4D printing, compares different additive manufacturing techniques for LCE, and highlights emerging applications in the field of soft robotics and biomedical technologies. Despite rapid progress in LCE, challenges remain in biocompatibility, long-term durability and manufacturing scalability. Overall, innovations in 4D printing of LCEs underscores both the promise and the challenges of these materials, pointing toward their transformative role in enabling next-generation soft robotic and biomedical technologies.

The article examines the synthesis and electrophysical properties of spinel ferrite ZnFe₂O₄, produced using the sol–gel method with a solid-state finishing process; as well as through classical ceramic technology with mechanochemical activation. The study includes a detailed analysis of the phase composition and crystalline structure using X-ray diffraction; infrared spectroscopy; mass spectrometry; and thermogravimetric and differential thermal analyses. These methods help identify thermal effects and the stages of synthesis. Impedance spectroscopy is used to investigate the electrophysical properties, revealing a significant influence of firing temperature on electrical ionic conductivity. The results show that the electrophysical properties differ based on the synthesis conditions and methods. This suggests potential applications for ZnFe₂O₄ as a cathode material in metal-ion batteries. The work highlights the importance of optimizing synthesis conditions to achieve high-performance characteristics in electrode materials.

This study presents a systematic approach to enhancing the mechanical performance of composite materials for submarine applications by quantitatively evaluating and controlling internal micro-voids generated during the manufacturing process. Three non-destructive evaluation techniques—ultrasonic testing, optical microscopy, and micro-computed tomography (Micro-CT)—were employed to assess the void content in fiber-reinforced composite specimens fabricated under various processing conditions. Tensile and flexural strength tests were conducted to investigate the correlation between the void content and mechanical properties. Among the methods, ultrasonic testing exhibited the strongest negative correlation (correlation coefficient = −0.703), confirming its effectiveness as a representative non-destructive evaluation technique. Furthermore, the statistical design of experiments, including factorial design, steepest ascent method, and response surface methodology (RSM), identified defoamer concentration and mixing time as the most influential process parameters in void reduction. The optimal processing conditions were determined to be 0.049% defoamer and 232 min of mixing. Under these conditions, the void content was minimized, and the mechanical properties were significantly improved. These findings offer practical guidance for void control and non-destructive evaluation in large-scale composite structures, contributing to improved reliability in underwater structural applications.