Photocatalysis with atomically thin sheets.

Atomically thin sheets (e.g., graphene and monolayer molybdenum disulfide) are ideal optical and reaction platforms. They provide opportunities for deciphering some important and often elusive photocatalytic phenomena related to electronic band structures and photo-charges. In parallel, in such thin sheets, fine tuning of photocatalytic properties can be achieved. These include atomic-level regulation of electronic band structures and atomic-level steering of charge separation and transfer. Herein, we review the physics and chemistry of electronic band structures and photo-charges, as well as their state-of-the-art characterization techniques, before delving into their atomic-level deciphering and mastery on the platform of atomically thin sheets.

Highly Stretchable, Repairable, and Tough Nanocomposite Hydrogel Physically Cross-linked by Hydrophobic Interactions and Reinforced by Surface-Grafted Hydrophobized Cellulose Nanocrystals.

Highly stretchable, repairable, and tough nanocomposite hydrogels are designed by incorporating hydrophobic carbon chains to create first-layer cross-linking among the polymer matrix and monomer-modified polymerizable yet hydrophobic nanofillers to create second-layer strong polymer-nanofiller clusters involving mostly covalent bonds and electrostatic interactions. The hydrogels are synthesized from three main components: hydrophobic monomer DMAPMA-C18 by reacting N-[3-(dimethylamino)propyl]methacrylamide] (DMAPMA) with 1-bromooctadecane, monomer N,N-dimethylacrylamide (DMAc), and monomer-modified polymerizable hydrophobized cellulose nanocrystal(CNC-G) obtained by reacting CNC with 3-trimethoxysily propyl methacrylate. The polymerization of DMAPMA-C18 and DMAc and physical cross-linking due to the hydrophobic interactions between C18 chains make DMAPMA-C18/DMAc hydrogel. The additional introduction of CNC-G brings more interactions into the final hydrogel (DMAPMA-C18/DMAc/CNC-G): the covalent bonds between CNC-G and DMAPMA-C18/DMAc, hydrophobic interactions, electrostatic interactions between negatively charged CNC-G and positively charged DMAPMA-C18, and hydrogen bonds. The optimum DMAPMA-C18/DMAc/CNC-G hydrogel exhibits excellent mechanical performance with elongation stress of 1085 ± 14 kPa, strain of 4106 ± 311%, toughness of 3.35 × 104  kJ m-3 , Young's modulus of 844 kPa, and compression stress of 5.18 MPa at 85% strain. Besides, the hydrogel exhibits good repairability and promising adhesive ability (83-260 kN m-2 toward various surfaces).

2D Transition Metal Dichalcogenides for Photocatalysis.

Two-dimensional (2D) transition metal dichalcogenides (TMDs), a rising star in the post-graphene era, are fundamentally and technologically intriguing for photocatalysis. Their extraordinary electronic, optical, and chemical properties endow them as promising materials for effectively harvesting light and catalyzing the redox reaction in photocatalysis. Here, we present a tutorial-style review of the field of 2D TMDs for photocatalysis to educate researchers (especially the new-comers), which begins with a brief introduction of the fundamentals of 2D TMDs and photocatalysis along with the synthesis of this type of material, then look deeply into the merits of 2D TMDs as co-catalysts and active photocatalysts, followed by an overview of the challenges and corresponding strategies of 2D TMDs for photocatalysis, and finally look ahead this topic.

Ultrastretchable, Adhesive, and Antibacterial Hydrogel with Robust Spinnability for Manufacturing Strong Hydrogel Micro/Nanofibers.

The ultrastretchable (over 12 400%) hydrogel with long-lasting adhesion, strong antibacterial activity, and robust spinnability is developed based on the oxidative decarboxylation and quinone-catechol reversible redox reaction induced by Ag-lignin nanoparticles in a precursor solution containing citric acid (CA), acrylic acid (AA), and poly (acrylamide-co-acrylic acid) (P(AAm-co-AA)). With massive reversible interactions including hydrogen bonds and electrostatic forces, such hydrogel exhibits promising injectability and is facilely spun via manual drawing, draw-spinning, and electrospinning for manufacturing strong hydrogel micro/nanofibers. The resulting fibers exhibit excellent mechanical properties, including tensile stress of 422.0 MPa, strain of 86.5%, Young's modulus of 8.7 GPa, and toughness of 281.6 MJ m-3 . The hydrogel microfibers obtained from a house-built spinner are scaled-up fabricated while retaining promising mechanical properties, as evidenced by lifting a load (317.2 g) using the spun fibers of ≈33 000 times lighter weight (9.5 mg), indicating their great potentials in the applications such as net and safety cord which require robust mechanical properties. Moreover, assisted by a commercial electrospinning machine, nanosized hydrogel fibers are facilely spun on personal protective equipment such as a mask to offer an antiseptic coating with near 100% killing efficiency against airborne bacteria aerosols, demonstrating the capability of spun hydrogel fibers on disinfection-related applications.

Lipase-Immobilized Cellulosic Capsules with Water Absorbency for Enhanced Pickering Interfacial Biocatalysis.

Lipase-immobilized cellulosic capsules consisting of hydrophobic ethyl cellulose (EC) and hydrophilic carboxymethyl cellulose (CMC) were developed with a promising interfacial activity and water absorbency for the enhanced Pickering interfacial biocatalysis. Lipase was physically immobilized with water-absorbent materials (CMC) via hydrogen bonding and electrostatic interactions and acted as the interior catalytic core of the capsule. The interfacially active EC worked as the exterior shell, enabling capsules to stabilize the oil-in-water Pickering emulsion for the subsequent Pickering interfacial catalysis. The capsules with CMC created interior water-rich conditions to improve the conformational and enzymatic activity of the immobilized lipase. Compared with capsules without water-absorbent materials, the capsules with CMC enhanced the efficiency of the Pickering interfacial catalysis for the esterification of oleic acid and 1-octanol by 12%. Immobilized with a small amount of lipase (0.0625 g/g), the cellulosic capsules with water absorbency could convert 50.8% of the reactants after 10 h under room temperature, significantly higher than that by the same amount of free lipase in the biphasic system (15%) and a Pickering emulsion (24.1%) stabilized by empty capsules (without lipase). Moreover, the cellulosic capsules could be recycled by simple centrifugation while retaining their high relative catalytic activity for at least eight cycles, demonstrating their sustainable catalytic performance.

Buckling Effect of Sole Zeolitic Imidazolate Framework-8 Nanoparticles Adsorbed at the Water/Oil Interface.

The buckling phenomenon of sole zeolitic imidazolate framework-8 (ZIF-8) particles adsorbed at the water/oil interface was systematically studied. The droplet of ZIF-8 water dispersion was pended in oil for a certain time period and manually extracted to decrease the volume. With the reduction of interfacial area, the ZIF-8 particles were jammed together to form a wrinkling solid film at the water/oil interface, which could withstand the extraction of the droplet and be regenerated. The size and concentration of the particles affected the assembly kinetics. The rapidest assembly was observed for the medium-sized ZIF-8 particles (m-ZIF-8) among the three sizes tested (1.81 µm, 258 nm, and 51 nm). The droplet of 0.91 wt % m-ZIF-8 reached a nearly full surface coverage in 13 min, faster than those with the lower concentration of 0.46 or 0.28 wt %. The pH of the solution, ranging between 6 and 10.7, affected both the assembly kinetics and film stability. Cryo-scanning electron microscopy images of frozen m-ZIF-8-stabilized Picking emulsions showed a monolayer of ZIF-8 wetted by both oil and water phases. The observed buckling effect could be attributed to the stable adsorption of ZIF-8 at the water/oil interface and the interparticle interactions, related to the unique surface chemistry and polyhedral shape of the ZIF-8 crystals. This work provided some understanding on the interfacial property of ZIF-8 and the mechanism of sole ZIF-8-stabilized Pickering emulsions.

Probing the Self-Assembly and Nonlinear Friction Behavior of Confined Gold Nano-Particles.

For the wide application of nanoparticles (NPs) (e.g., in nanotribology), it is of fundamental and practical importance to understand the self-assembly and lubrication behavior of confined NPs. In this work, a systematic study was conducted to probe the assembly and associated surface forces of spherical gold nanoparticles (Au NPs, diameter ∼5 nm) confined between pairs of mica (negatively charged) and (3-aminopropyl)triethoxysilane modified mica (APTES-mica, positively charged) surfaces using a surface forces apparatus (SFA) under aqueous conditions. It is observed that Au NPs were squeezed out of the confined gap between two mica surfaces during the loading process, resulting from the repulsive electric-double layer force. In contrast, multilayers of Au NPs were confined between two APTES-mica surfaces because of the attractive double-layer force between oppositely charged Au NPs and APTES-mica. Interestingly, the interaction between Au NPs and APTES-mica is stronger than the interactions between Au NPs, resulting in the rearrangement of the confined Au NPs under shearing. Importantly, a large friction coefficient (µ > 0.7) with unexpected nonlinear stick-slip friction was observed when sliding two APTES-mica surfaces with thin layers of Au NPs (∼20 nm) confined in between. The observed stick-slip motion could be explained by the velocity-dependent friction model where a critical shear velocity was required for transiting from stick-slip to smooth sliding. Our study provides useful information on the assembly and interaction forces of confined nanoparticles on charged surfaces, with implications for predicting the behaviors of NPs under confinement in various engineering applications.

Probing molecular interactions of PEGylated chitosan in aqueous solutions using a surface force apparatus.

PEGylation can modify the physicochemical properties of native chitosan and improves its water solubility. PEGylated chitosan has been widely used as a gene/drug delivery vector by forming a polyelectrolyte complex (PEC) in biomedical engineering. The molecular interactions of PEGylated chitosan play a critical role in forming the core-shell structure of the complexes. In this work, we systematically investigated the cohesive interaction between PEGylated chitosan films using a surface forces apparatus (SFA) under different solution conditions, and the corresponding morphology change was characterized using atomic force microscopy (AFM). The force measurements demonstrated that the cohesion could be enhanced by increasing the contact time and the PEGylation degree, but could be weakened by increasing the solution pH, which is closely related to the morphology change of the PEGylated chitosan films. The strong cohesion of PEGylated chitosan, as compared to that of native chitosan, is primarily attributed to improved polymer solubility and flexibility, and enhanced formation of hydrogen bonds between the polymer chains. In addition, continuously increasing the PEGylation degree was found to be less effective in further strengthening the cohesion at relatively high pH (e.g., pH ∼ 8.5), which is most likely due to the repulsion originating from the formation of dense hydration PEG shells. Our results provide useful nanomechanical insights into the fundamental understanding of the interaction mechanism of PEGylated chitosan, with implications for the development of novel and effective gene/drug carriers in bioengineering.

Probing Molecular Interactions of Asphaltenes in Heptol Using a Surface Forces Apparatus: Implications on Stability of Water-in-Oil Emulsions.

The behaviors and molecular interactions of asphaltenes are related to many challenging issues in oil production. In this study, the molecular interaction mechanism of asphaltenes in Heptol solvents of varying toluene/n-heptane ratio were directly measured using a surface forces apparatus (SFA). The results showed that the interactions between asphaltene surfaces gradually changed from pure repulsion to weak adhesion as the weight ratio of toluene (ω) in Heptol decreased from ω = 1 to 0. The measured repulsion was mainly due to the steric interactions between swelling asphaltene molecules and/aggregates. The micropipet technique was applied to test the stability of two water-in-oil emulsion droplets attached to glass pipettes. A computer-controlled 4-roll mill fluidic device was also built in-house to investigate the interaction of free-suspending water-in-oil emulsions under dynamic flow conditions. Both micropipet and 4-roll mill fluidic tests demonstrate that asphaltenes adsorbed at oil/water interfaces play a critical role in stabilizing the emulsion drops, in agreement with the repulsion measured between asphaltene surfaces in toluene using SFA, and that interfacial sliding or shearing is generally required to destabilize the protective interfacial apshaltene layers which facilitates the coalescence of emulsion drops. Our results provide insights into the fundamental understanding of molecular interaction mechanisms of asphaltenes in organic solvents and stabilization/destabilization behaviors of water-in-oil emulsions with asphaltenes.

The impact of cellulose nanocrystals on the aggregation and initial adhesion of Pseudomonas fluorescens bacteria.

Deposition on silica surfaces of two Pseudomonas fluorescens strains (CHA0 and CHA19-WS) having different extracellular polymeric substance (EPS) producing capacities was studied in the absence and presence of cellulose nanocrystals (CNCs). Batch (batch soaking) and continuous flow (quartz crystal microbalance with dissipation) methods were used to evaluate the impact of CNCs on bacterial initial adhesion. This study demonstrated that bacterial initial adhesion to solid surfaces can be significantly hindered by CNCs using both methods. In the presence of CNCs, it was observed that bacteria with more EPS aggregated more significantly compared to bacteria with less EPS, and that bacterial deposition under this condition decreased to a greater extent. The classic DLVO theory failed to predict bacterial adhesion behavior in this study. A detailed discussion is provided regarding potential antibacterial adhesion mechanisms of CNCs.

In vivo residue-specific dopa-incorporated engineered mussel bioglue with enhanced adhesion and water resistance.

Misaminoacylation of 3,4-dihydroxyphenylalanine (Dopa) molecules to tRNA(Tyr) by endogenous tyrosyl-tRNA synthetase allowed the quantitative replacement of tyrosine residues with a yield of over 90 % by an in vivo residue-specific incorporation strategy, to create, for the first time, engineered mussel adhesive proteins (MAPs) in Escherichia coli with a very high Dopa content, close to that of natural MAPs. The Dopa-incorporated MAPs exhibited a superior surface adhesion and water resistance ability by assistance of Dopa-mediated interactions including the oxidative Dopa cross-linking, and furthermore, showed underwater adhesive properties comparable to those of natural MAPs. These results propose promising use of Dopa-incorporated engineered MAPs as bioglues or adhesive hydrogels for practical underwater applications.

A review of high internal phase Pickering emulsions: Stabilization, rheology, and 3D printing application.

High internal phase Pickering emulsion (HIPPE) is renowned for its exceptionally high-volume fraction of internal phase, leading to flocculated yet deformed emulsion droplets and unique rheological behaviors such as shear-thinning property, viscoelasticity, and thixotropic recovery. Alongside the inherent features of regular emulsion systems, such as large interfacial area and well-mixture of two immiscible liquids, the HIPPEs have been emerging as building blocks to construct three-dimensional (3D) scaffolds with customized structures and programmable functions using an extrusion-based 3D printing technique, making 3D-printed HIPPE-based scaffolds attract widespread interest from various fields such as food science, biotechnology, environmental science, and energy transfer. Herein, the recent advances in preparing suitable HIPPEs as 3D printing inks for various applied fields are reviewed. This work begins with the stabilization mechanism of HIPPEs, followed by introducing the origin of their distinctive rheological behaviors and strategies to adjust the rheological behaviors to prepare more eligible HIPPEs as printing inks. Then, the compatibility between extrusion-based 3D printing and HIPPEs as building blocks was discussed, followed by a summary of the potential applications using 3D-printed HIPPE-based scaffolds. Finally, limitations and future perspectives on preparing HIPPE-based materials using extrusion-based 3D printing were presented.

Intercalation in 2D materials and in situ studies.

Intercalation of atoms, ions and molecules is a powerful tool for altering or tuning the properties - interlayer interactions, in-plane bonding configurations, Fermi-level energies, electronic band structures and spin-orbit coupling - of 2D materials. Intercalation can induce property changes in materials related to photonics, electronics, optoelectronics, thermoelectricity, magnetism, catalysis and energy storage, unlocking or improving the potential of 2D materials in present and future applications. In situ imaging and spectroscopy technologies are used to visualize and trace intercalation processes. These techniques provide the opportunity for deciphering important and often elusive intercalation dynamics, chemomechanics and mechanisms, such as the intercalation pathways, reversibility, uniformity and speed. In this Review, we discuss intercalation in 2D materials, beginning with a brief introduction of the intercalation strategies, then we look into the atomic and intrinsic effects of intercalation, followed by an overview of their in situ studies, and finally provide our outlook.

Highly Dispersed Ni Atoms and O3 Promote Room-Temperature Catalytic Oxidation.

Transition metal oxides are promising catalysts for catalytic oxidation reactions but are hampered by low room-temperature activities. Such low activities are normally caused by sparse reactive sites and insufficient capacity for molecular oxygen (O2) activation. Here, we present a dual-stimulation strategy to tackle these two issues. Specifically, we import highly dispersed nickel (Ni) atoms onto MnO2 to enrich its oxygen vacancies (reactive sites). Then, we use molecular ozone (O3) with a lower activation energy as an oxidant instead of molecular O2. With such dual stimulations, the constructed O3-Ni/MnO2 catalytic system shows boosted room-temperature activity for toluene oxidation with a toluene conversion of up to 98%, compared with the O3-MnO2 (Ni-free) system with only 50% conversion and the inactive O2-Ni/MnO2 (O3-free) system. This leap realizes efficient room-temperature catalytic oxidation of transition metal oxides, which is constantly pursued but has always been difficult to truly achieve.

Design and fabrication strategies of cellulose nanocrystal-based hydrogel and its highlighted application using 3D printing: A review.

To eliminate the potential toxicity and biological incompatibility from hydrogels prepared using synthetic polymers, researchers have paid tremendous efforts to design hydrogels using nature-obtainable biopolymers due to their outstanding biocompatibility, low cytotoxicity, and no secondary hazards. Among the biopolymers, cellulose nanocrystals (CNCs) have attracted ever-increasing interest from both academic and industrial sides because of their whisker nanostructure, high axial stiffness, high tensile strength, and abundant hydroxyl groups on the surface. CNCs can provide the three-dimensional (3D) hydrogels with enhanced mechanical properties and designed functions and, therefore, offering CNC-based composite hydrogel wide applications in the fields such as biomedical, tissue engineering, actuator, etc. In this review, we begin with the design rationales of the "CNC-only" hydrogel and CNC-based hydrogels, to illustrate the interactions between CNCs themselves or with the surrounding hydrogel backbones. Then, as a fashionable method, the extrusion-based 3D printing technique for fabricating and shaping CNC-based composite hydrogels was elaborately introduced, followed by a brief review of 3D printed CNC-based hydrogels in different fields. Finally, limitations and future directions of CNC-based hydrogels were discussed. We aim to provide a deeper understanding of CNC-based composite hydrogels in the aspects of rational design, fabrication strategy and highlighted applications in 3D printing.

Cd(II) adsorption on earth-abundant serpentine in aqueous environment: Role of interfacial ion specificity.

Adsorption of heavy metal ions (e.g., Cd(II)) on clay minerals significantly affects their transport and fate in natural and engineered waterbodies. To date, the role of interfacial ion specificity in the adsorption of Cd(II) on earth-abundant serpentine remains elusive. In this work, the adsorption of Cd(II) on serpentine at typical environment conditions (pH 4.5-5.0), particularly under the complex influence of common environmental anions (e.g., NO3-, SO42-) and cations (e.g., K+, Ca2+, Fe3+, Al3+) was systemically investigated. It was found that the adsorption of Cd(II) on serpentine surface due to the inner-sphere complexation could be negligibly affected by the anion type, yet the cations specifically modulated the Cd(II) adsorption. The presence of mono- and divalent cations moderately enhanced the Cd(II) adsorption by weakening the electrostatic double layer (EDL) repulsion between Cd(II) and Mg-O plane of serpentine, while trivalent cations significantly suppressed the adsorption of Cd(II) due to the competitive adsorption. Based on the spectroscopy analysis, Fe3+ and Al3+ were found to robustly bind the surface active sites of serpentine, thereby preventing the inner-sphere adsorption of Cd(II). The density functional theory (DFT) calculation indicated that Fe(III) and Al(III) exhibited the larger adsorption energy (Ead = -146.1 and -516.1 kcal mol-1, respectively) and stronger electron transfer capacity with serpentine compared to Cd(II) (Ead = -118.1 kcal mol-1), thus resulting in the formation of more stable Fe(III)-O and Al(III)-O inner-sphere complexes. This study provides valuable insights into the influence of interfacial ion specificity on the Cd(II) adsorption in terrestrial and aquatic environments.

Visible light laser direct-writing of high-resolution, biocompatible, super-multifunctional and tough hydrogels without photoinitiators in 30 s.

Currently, the lack of bioinks and long printing time limits the further development of biofabrication. Here we report a novel biocompatible, multi-functional and tough 3D printable hydrogel via visible light photocrosslinking of polyvinyl alcohol bearing styrylpyridinium group (PVA-SbQ). The high-resolution PVA-SbQ hydrogels with different designed shapes can be generated via laser direct-writing in 30 s without extra toxic crosslinkers or photoinitiators, and demonstrates excellent biocompatibility. The rapid laser direct-writing technology also results in a super-strong, tough hydrogel with excellent adhesive, swelling, self-healing, and photo-tunable properties due to the photodimerization of styrylpyridinium (SbQ) groups and the left-over massive amount of free hydroxyl groups in the hydrogel. For example, the maximum tensile strength, elongation, compressive strength adhesive strength of printed PVA-SbQ hydrogels can reach 1.0 MPa, 810 %, 33 MPa, 31 kPa, and 25,000 % respectively. And these properties can be adjusted by controlling the parameters for laser direct-writing. In addition, the introduced nitrogen cations by SbQ groups further endow hydrogels with the potential to develop novel functionality, which is demonstrated by integrating negatively charged nanocelluloses in the PVA-SbQ system to develop underwater adhesives, anti-freezing (-24.9 °C), and anti-bacterial hydrogels. This discovery opens multiple doors for developing PVA-SbQ based multi-functional hydrogel for various applications including biofabrication and tissue engineering.

Blowing-inspired ex situ preparation of ultrathin hydrogel coatings for visibly monitoring humidity and alkaline gas.

Compared with the in situ preparation of ultrathin hydrogel coatings through successive yet tedious steps, ex situ strategies decouple the steps and greatly enhance the maneuverability and convenience of preparing hydrogel coatings. However, the difficulty in preparing sub-micron-thick coatings limits the applicability of ex situ methods in nanotechnology. Herein, we report the ex situ preparation of centimeter-scale ultrathin hydrogel coatings by applying omnidirectional stretching toward pre-gelated hydrogels with necking behaviors. This process involves blowing a bubble directly from a pre-gelated hydrogel and subsequently transferring the resulting hydrogel bubble to different substrates. The as-fabricated coatings exhibit peak-shaped thickness variations, with the thinnest part as low as ∼5 nm and the thickest part controllable from ∼200 nm to several microns. This method can be universally applied to hydrogels with necking behavior triggered by internal particles with partial hydrophobicity. Due to the overall near- or sub-micron thickness and unique thickness distribution, the coatings present concentric rings of different interference colors. With such an observable optical characteristic, the as-prepared hydrogel coatings are applied as sensors to visibly monitor humidity changes or alkaline gas through the visibly observable expansion or contraction of concentric interferometry rings, which is triggered by adsorbing/desorbing the surrounding water or alkaline molecules and the resultant swelling/deswelling of the coatings, respectively. With the universality of the method, we believe that the ex situ strategy can be used as a simple yet efficient environmental nanotechnology to fabricate various types of nanometer-thick hydrogel coatings as detectors to sensitively and visibly monitor surrounding stimuli on demand.

Multifunctional fully biobased aerogels for water remediation: Applications for dye and heavy metal adsorption and oil/water separation.

Water ecosystem contamination from industrial pollutants is an emerging threat to both humans and native species, making it a point of global concern. In this work, fully biobased aerogels (FBAs) were developed by using low-cost cellulose filament (CF), chitosan (CS), citric acid (CA), and a simple and scalable approach, for water remediation applications. The FBAs displayed superior mechanical properties (up to ∼65 kPa m3 kg-1 specific Young's modulus and ∼111 kJ/m3 energy absorption) due to CA acting as a covalent crosslinker in addition to the natural hydrogen bonding and electrostatic interactions between CF and CS. The addition of CS and CA increased the variety of functional groups (carboxylic acid, hydroxyl and amines) on the materials' surface, resulting in super-high dye and heavy metal adsorption capacities (619 mg/g and 206 mg/g for methylene blue and copper, respectively). Further modification of FBAs with a simple approach using methyltrimethoxysilane endowed aerogel oleophilic and hydrophobic properties. The developed FBAs showed a fast performance in water and oil/organic solvents separation with more than 96% efficiency. Besides, the FBA sorbents could be regenerated and reused for multiple cycles without any significant impact on their performance. Moreover, thanks to the presence of amine groups by addition of CS, FBAs also displayed antibacterial properties by preventing the growth of Escherichia coli on their surface. This work demonstrates the preparation of FBAs from abundant, sustainable, and inexpensive natural resources for applications in wastewater purification.

Development of Antifreezing, Printable, Adhesive, Tough, Biocompatible, High-Water Content Hydrogel for Versatile Applications.

Hydrogels with different functionalities such as printability, antifreezing properties, adhesion, biocompatibility, and toughness are being continually developed. However, it has been extremely challenging to design adhesive, antifreezing, tough, and biocompatible multifunctional hydrogels with complex shapes simultaneously and prepare them in a short period. In this paper, novel composite hydrogels, which consist of poly(vinyl alcohol) grafted with styrylpyridinium group (PVA-SbQ) and TEMPO-oxidized cellulose nanofibrils (CNF), were successfully synthesized via UV photo-cross-linking. In addition to UV photo-cross-linking, the PVA-SbQ/CNF hydrogels with different shapes could be rapidly printed by facile visible light-based stereolithography printing and laser direct-writing without any photoinitiators in 3 min and 30 s, respectively. The results show that PVA-SbQ/CNF hydrogels are biocompatible because there are no photoinitiators and cross-linkers required during the printing process under visible light. Moreover, the adhesive, antifreezing, mechanical properties, and water-binding capacity of PVA-SbQ/CNF with high-water contents improved significantly as the CNF contents increased. Such hydrogels, which combine multiple advantages, present great potential for application in wound dressings and portable devices with specific requirements for shapes, adhesion, toughness, and tolerance in extreme environments such as dry environments and low temperatures.