Herein, we present a novel, binder-free, stereolithography-based 3D printing approach for fabricating complex sol-gel silica glassy structures at the centimeter scale using only sol-gel chemistry. Unlike conventional methods that rely on organic photopolymerizable resins or hybrid monomers, our process eliminates the need for sacrificial organic binders and the associated high temperature debinding steps. The proposed method utilizes a photo-base generator to induce a localized pH change upon irradiation, triggering spatially controlled sol-gel polymerization. After printing and rinsing, the resulting gel structures are transformed into mesoporous silica through low-temperature heat treatment at 250 ℃. The printed silica objects exhibit moderate transparency, minimal shrinkage (∼25 %), and a well-defined mesoporous structure with pore sizes predominantly in the 4-8 nm range. Solid-state ²⁹Si NMR spectroscopy and energy-dispersive X-ray spectroscopy confirm enhanced silica condensation under vacuum, achieving a near-theoretical Si:O atomic ratio. This approach enables the scalable production of binder-free, high-resolution silica objects with potential applications in optics, biomedical engineering, and microfluidics.

Soft robotics is a rapidly evolving field that leverages the unique properties of compliant, flexible materials to create robots that are capable of complex and adaptive behaviors. Unlike traditional rigid robots, soft robots rely on the properties of soft materials, which enable them to safely interact with humans, manipulate delicate objects, and perform various locomotion processes. This review provides a comprehensive overview of the development process of soft robots by additive manufacturing with a particular focus on the chemical aspects of the materials involved. The types of materials used in soft robotics, highlighting their properties, applications, and the role of their chemical composition in performance, are presented. The review then explores fabrication methods, detailing their chemical underpinnings, advantages, and limitations, followed by presenting common design methods used to optimize soft robots. Finally, the review discusses the diverse applications of soft robots across various domains, including medical, locomotion, manipulation, and wearable devices. By covering every stage of the additive manufactured soft robot, from material selection to application, this review aims to offer a deep and comprehensive understanding of this field.

Adhesives are vital in industries ranging from aerospace to consumer electronics. However, their reliance on non-recyclable polymers makes them suitable for one-time use and results in significant economic and environmental challenges. Reversible adhesives, based on covalent adaptable networks, address these issues and open possibilities for applications, including recyclable multi-layer packaging, removable labels, and fully recyclable electronics – batteries, smartphones, etc. Despite progress in dynamic and reversible bonds, current solutions often compromise performance or the ability to detach from substrates. This study proposes reversible high-performance adhesives that can undergo cycles of bonding-debonding without commonly reported need to add solvent, high-temperature processing or use deep-UV irradiation while maintaining adhesives' functionality and reducing environmental impact. The bonding is done by rapid photocuring, which occurs within 30 seconds under irradiation at a wide range of visible wavelengths (400–650 nm) while achieving constant adhesion strength across diverse substrates, including underwater adhesion. De-bonding is achieved using a simple household microwave. Furthermore, the adhesive's transparency and high refractive index enable its use in various optical applications, whereas its robustness in wet conditions expands its potential for bioadaptive or underwater systems. This adhesive represents a significant step toward sustainable adhesives that seamlessly integrate high performance with circular-economy principles.

Stereolithography printing of ceramics and glass relies on compositions containing dispersed particles in photopolymerizable solutions. A new approach based on utilizing sol–gel precursor solutions has been introduced in recent years, which overcomes challenges in particle-based printing compositions, such as light scattering, particle sedimentation, and high viscosity. Following sol–gel and photopolymerization processes’ combination, this paper presents the methodologies for the 3D printing of complex ceramics and glass structures. This combination allows precise structure control, enabling dense or porous objects, transparent forms, and simple doping. These advantages are presented through the fabrication of porous γ-alumina, transparent silica glass, and chromium-doped α-alumina.

This study explores the utilization of digital light processing (DLP) printing to fabricate complex structures using native gelatin as the sole structural component for applications in biological implants. Unlike approaches relying on synthetic materials or chemically modified biopolymers, this research harnesses the inherent properties of gelatin to create biocompatible structures. The printing process is based on a crosslinking mechanism using a di-tyrosine formation initiated by visible light irradiation. Formulations containing gelatin were found to be printable at the maximum documented concentration of 30 wt%, thus allowing the fabrication of overhanging objects and open embedded. Cell adhesion and growth onto and within the gelatin-based 3D constructs were evaluated by examining two implant fabrication techniques: (1) cell seeding onto the printed scaffold and (2) printing compositions that contain cells (cell-laden). The preliminary biological experiments indicate that both the cell-seeding and cell-laden strategies enable making 3D cultures of chondrocytes within the gelatin constructs. The mechanical properties of the gelatin scaffolds have a compressive modulus akin to soft tissues, thus enabling the growth and proliferation of cells, and later degrade as the cells differentiate and form a grown cartilage. This study underscores the potential of utilizing non-modified protein-only bioinks in DLP printing to produce intricate 3D objects with high fidelity, paving the way for advancements in regenerative tissue engineering.

The additive manufacturing of hardmetals has attracted great attention recently but faces significant challenges in low printing resolution and low mechanical strength. Herein, the fabrication of hardmetal parts with complex structures and high surface quality by vat photopolymerization assisted with a sintering process has been achieved. This was enabled by in situ polymerization-induced microencapsulation of WC powder, which simultaneously enhances the photocuring ability and sedimentation stability of the WC-Co slurry. The WC powder is microencapsulated by a polystyrene (PS, WC@PS) coating with a thickness of ∼20 nm. The curing depth of the WC-Co slurry with WC@PS was dramatically increased from 32 to 336 μm compared to the slurry with original WC, exhibiting an average increment of 650%. The 3D-printed hardmetal parts exhibited a relative density of 99.5%, a Rockwell hardness of 86.9 HRA, and a surface roughness R_a of 2.26 μm, approaching the theoretical limits in classical powder metallurgy-derived WC-Co hardmetal parts. With high density and hardness, it is shown that a printed drilling bit can easily drill through metal sheets. This work paves a path for the vat photopolymerization 3D printing of miniature complex hardmetal components combined with high surface quality and high performance.

Stereolithography printing of ceramics and glass relies on compositions containing dispersed particles in photopolymerizable solutions. A new approach based on utilizing sol–gel precursor solutions has been introduced in recent years, which overcomes challenges in particle-based printing compositions, such as light scattering, particle sedimentation, and high viscosity. Following sol–gel and photopolymerization processes’ combination, this paper presents the methodologies for the 3D printing of complex ceramics and glass structures. This combination allows precise structure control, enabling dense or porous objects, transparent forms, and simple doping. These advantages are presented through the fabrication of porous γ-alumina, transparent silica glass, and chromium-doped α-alumina.

Printed electronics is based on the application of 2D and 3D printing technologies to fabricate electronic devices. To fabricate the printed electronic 2D and 3D devices with the required performance, it is necessary to properly select and tailor the conductive inks, which are often composed of nanomaterials, The main nanomaterials in conductive inks for 2D and 3D printed electronics contain conductive nanomaterials such as metal nanoparticles (NPs) and nanowires and carbon based nanomaterials: carbon black, graphene sheets, and carbon nanotubes (CNTs). All these materials were successfully applied for the fabrication of various electronic devices such as electrical circuits, transparent electrodes, flexible thin film transistors, RFID antennas, photovoltaic devices, and flexible touch panels. In this paper, we focus on the basic properties of these nanomaterials, in view of their application in conductive inks, on obtaining conductive patterns by 2D and 3D printing, and on various methods of post-printing treatment. In the last section, a perspective on future needs and applications will be presented, including emerging technologies.

The growing demand for dexterous and autonomous robotic manipulation highlights the need for advanced sensing and control strategies, particularly for slip prevention. Although soft grippers provide intrinsic compliance and adaptability, their effectiveness is often limited by the lack of real-time sensory feedback and the complexity of soft actuator dynamics. Inspired by human tactile perception, we developed a bioarchitectonics-inspired soft slip sensor with a three-dimensional structure that leverages crack and stress concentration to enhance sensitivity to incipient slip and shear force. Complementarily, a soft gripper with a linear pressure-to-force response was engineered to enable stable and predictable force modulation. The flexible slip sensors were conformally integrated onto the grippers, forming a fully perceptive soft robotic system capable of detecting early-stage slippage and investigating interfacial frictional properties. This integration establishes a closed-loop sensorimotor framework that notably improves the reliability and adaptability of soft robotic grasping across a wide range of real-world applications.

Technological advancements drive the demand for smart, flexible, and sustainable devices capable of integration into daily life. Pressure sensors, particularly those utilizing halide perovskites, face key challenges in sensitivity, stability, and integration with soft systems. This study focuses on the investigation of quasi-two-dimensional (2D) perovskite pressure sensors, where the perovskite is embedded within a polyvinylidene fluoride (PVDF) polymer matrix and protected by a polydimethylsiloxane (PDMS) polymer layer. The improvement in the performance of the pressure sensors is achieved through the optimization of the solvent composition, perovskite:PVDF ratio, and thickness of the PDMS layer, with a deep understanding of the morphological structure's influence on piezoelectric properties. Our perovskite layer achieves a high piezoelectric coefficient (d₃₃) of 31.26 pm V⁻¹, surpassing previously reported values for halide perovskites. Unlike previous studies, we systematically investigate the correlation between the PDMS thickness and the piezoelectric response, identifying a critical thickness threshold (∼23 μm) beyond which sensing is suppressed. The devices demonstrate pressure sensitivity in the absence of any external power source and maintain reliable performance for 1000 cycles and up to 60 days under ambient conditions. Successful integration of the sensors into soft robotic grippers while also demonstrating sensitivity to various weights highlights their potential for application in fields such as soft robotics and healthcare.

Sol-gel glass processing gained scientific and technological importance in 1970, generating a new approach to preparing ceramics and homogenous glasses at low temperatures. Since then, sol-gel technology has continued to progress with an improvement of existing functional materials and the exploration of novel materials to be utilized in many research areas such as electronics, chemistry, mechanics, pharmacy, and medicine. The overall structure and properties of glasses synthesized by sol-gel technology are similar to those of melt-formed glasses that are obtained by using traditional processing methods. However, due to the high cost of raw materials and long processing time with very fine-tuned processing requirements for sol-gel approaches, they are not typically used in the large-scale commercial production of ordinary silicate glass pieces. This chapter will describe the theory and chemistry of sol-gel processes, the routes to utilize this process to make 3D objects, and the relevance of such processes to the field of 3D printing of glass.