Simultaneous Polymerization Acceleration and Mechanical Enhancement for Printing a Biomimetic PEDOT Adhesive by Coordinative and Orthogonal Ruthenium Photochemistry.

Conductive hydrogels are promising material candidates in fields ranging from flexible sensors and electronic skin applications to personalized medical monitoring. However, developing intrinsically conductive polymer hydrogels (ICPHs) with high mechanical properties and excellent printability is still challenging. Here, we introduce a simultaneous polymerization acceleration and mechanical enhancement (SPAME) strategy to construct PEDOT-based ICPHs via the rational design of coordinative and orthogonal ruthenium photochemistry (CORP).

Customizable Low-Friction Tough Hydrogels for Potential Cartilage Tissue Engineering by a Rapid Orthogonal Photoreactive 3D-Printing Design.

Hydrogels have demonstrated wide applications in tissue engineering, but it is still challenging to develop strong, customizable, low-friction artificial scaffolds. Here, we report a rapid orthogonal photoreactive 3D-printing (ROP3P) strategy to achieve the design of high-performance hydrogels in tens of minutes. The orthogonal ruthenium chemistry enables the formation of multinetworks in hydrogels via phenol-coupling reaction and traditional radical polymerization.

Trifunctional Microgel-Mediated Preparation and Toughening of Printable High-Performance Chitosan Hydrogels for Underwater Communications.

Natural and biocompatible chitosan has demonstrated wide applications. However, rapidly fabricating high-performance chitosan hydrogels in one-step controllable processes is still a challenge for some advanced applications. Here, we report a trifunctional microgel-mediated photochemical (TMMP) strategy to achieve the fabrication of printable tough chitosan-based hydrogels (PTCHs) in seconds.

Protein Crystallization-Mediated Self-Strengthening of High-Performance Printable Conducting Organohydrogels.

Conductive polymers have many advanced applications, but there is still an important target in developing a general and straightforward strategy for printable, mechanically stable, and durable organohydrogels with typical conducting polymers of, for example, polypyrrole, polyaniline, or poly(3,4-ethylenedioxythiophene). Here we report a protein crystallization-mediated self-strengthening strategy to fabricate printable conducting organohydrogels with the combination of rational photochemistry design. Such organohydrogels are one-step prepared via rapidly and orthogonally controllable photopolymerizations of pyrroles and gelatin protein in tens of seconds.

Photoredox-Mediated Designing and Regulating Metal-Coordinate Hydrogels for Programmable Soft 3D-Printed Actuators.

Metal-organic coordination is widely applied for designing responsive polymers and soft devices. But it is still a challenge to prepare redox-responsive actuators with complicated structures, limiting their advanced applications in material and engineering fields. Here, we report a photoredox-mediated designing and regulating strategy to fabricate metal-coordinate hydrogels with the catalysis of Ru(II)/Co(III) under visible-light irradiation in seconds.

Bifunctional Phenol-Enabled Sequential Polymerization Strategy for Printable Tough Hydrogels.

Hydrogels are promising material candidates in engineering soft robotics, mechanical sensors, biomimetic regenerative medicine, etc. However, developing multinetwork hydrogels with high mechanical properties and excellent printability are still challenging. Here, a bifunctional phenol-enabled sequential polymerization (BPSP) strategy is reported to fabricate high-performance multinetwork hydrogels under the orthogonal catalysis of efficient ruthenium photochemistry.

Visible-Light-Mediated Nano-biomineralization of Customizable Tough Hydrogels for Biomimetic Tissue Engineering.

Biomineralized tough hydrogels (BTHs) have advanced applications in the fields of soft bioelectronics and biomimetic tissue engineering. But the development of rapid and general photomineralization strategies for one-step fabrication of customizable BTHs is still a challenging task. Here we report a straightforward, low-cost visible-light-mediated nano-biomineralization (VLMNB) strategy a rational design of a phosphate source and efficient ruthenium photochemistry.

A new soft-matter material with old chemistry: Passerini multicomponent polymerization-induced assembly of AIE-active double-helical polymers with rapid visible-light degradability.

Mimicking the superstructures and functions of natural chiral materials is beneficial to understand specific biological activities in living organisms and broaden applications in the fields of chemistry and materials sciences. However, it is still a great challenge to construct water-soluble, double-helical polymers with multiple responsiveness. Herein, we report for the first time a straightforward, general strategy to address this issue by taking advantage of Passerini multicomponent polymerization-induced assembly (PMPIA).

Orthogonal photochemistry-assisted printing of 3D tough and stretchable conductive hydrogels.

3D-printing tough conductive hydrogels (TCHs) with complex structures is still a challenging task in related fields due to their inherent contrasting multinetworks, uncontrollable and slow polymerization of conductive components. Here we report an orthogonal photochemistry-assisted printing (OPAP) strategy to make 3D TCHs in one-pot via the combination of rational visible-light-chemistry design and reliable extrusion printing technique. This orthogonal chemistry is rapid, controllable, and simultaneously achieve the photopolymerization of EDOT and phenol-coupling reaction, leading to the construction of tough hydrogels in a short time (t ~30 s).

Rapidly Visible-Light-Mediated Photogelations for One-Step Engineering Multifunctional Tough Hydrogel Tubes.

Hydrogel tubes as one kind of perfusable tubular materials, show promising applications in a wide spectrum of fields. However, there is still a great challenge to design a rapid, biocompatible, and straightforward strategy for one-step engineering tough hydrogel tubes, which have excellent mechanical properties, unique resilience, and multiple functions. Herein, we explore visible-light-mediated orthogonal photochemistry to achieve the fabrication of tough hydrogel tubes with double networks via a coaxial-nozzle spinning technique under short blue-light irradiation (∼20 s).

Visible-light-assisted multimechanism design for one-step engineering tough hydrogels in seconds.

Tough hydrogels that are capable of efficient mechanical energy dissipation and withstanding large strains have potential applications in diverse areas. However, most reported fabrication strategies are performed in multiple steps with long-time UV irradiation or heating at high temperatures, limiting their biological and industrial applications. Hydrogels formed with a single pair of mechanisms are unstable in harsh conditions.

Direct 3D Printing of Hybrid Nanofiber-Based Nanocomposites for Highly Conductive and Shape Memory Applications.

Three-dimensional (3D) printing with conductive polymer nanocomposites provides an attractive strategy for the "on-demand" fabrication of electrical devices. This paper demonstrates a family of highly conductive multimaterial composites that can be directly printed into ready-to-use multifunctional electrical devices using a flexible solvent-cast 3D printing technique. The new material design leverages the high aspect ratio and low contact resistance of the hybrid silver-coated carbon nanofibers (Ag@CNFs) with the excellent 3D printability of the thermoplastic polymer.

Direct-Write Fabrication of 4D Active Shape-Changing Structures Based on a Shape Memory Polymer and Its Nanocomposite.

Four-dimensional (4D) active shape-changing structures based on shape memory polymers (SMPs) and shape memory nanocomposites (SMNCs) are able to be controlled in both space and time and have attracted increasing attention worldwide. However, conventional processing approaches have restricted the design space of such smart structures. Herein, 4D active shape-changing architectures in custom-defined geometries exhibiting thermally and remotely actuated behaviors are achieved by direct-write printing of ultraviolet (UV) cross-linking poly(lactic acid)-based inks.

Shape-memory polymer nanocomposites with a 3D conductive network for bidirectional actuation and locomotion application.

Electrical stimulation of shape-memory polymers (SMPs) has many advantages over thermal methods; creating an efficient conductive path through the bulk polymers is essential for developing high performance electroactive systems. Here, we show that a three-dimensional (3D) porous carbon nanotube sponge can serve as a built-in integral conductive network to provide internal, homogeneous, in situ Joule heating for shape-memory polymers, thus significantly improving the mechanical and thermal behavior of SMPs. As a result, the 3D nanocomposites show a fast response and produce large exerting forces (with a maximum flexural stress of 14.

Fast Triggering of Shape Memory Polymers using an Embedded Carbon Nanotube Sponge Network.

In this work, a 3-D porous carbon nanotube sponge (CNTS) was embedded within a shape memory polymer (SMPs) matrix. We demonstrate complete infiltration and filling of the SMPs into the CNTS by capillary force without any damage to the CNTS structure. With only ~0.