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The microscopically structural switching of supramolecular networks endows programmable gel materials with dynamic hiding properties and functionalities. However, the reconstruction of supramolecular network will destroy the programming information imprinted on the original network structure, making it difficult to restore to the original state. Here, a novel intelligent programmable photonic gel composed of cellulose nanocrystals (CNC) and acrylamide is constructed. The mechanical properties and optical signals of gel can be switched reversibly on demand by reasonably designing the winding and compression between molecular structures. Under this conversion mechanism, the rigid "skeleton" constructed from the CNC chiral structure perfectly acts as the coding substrate. Importantly, even after multiple dynamic switching of the supramolecular network, the encoded information can be displayed completely and accurately on the CNC chiral structure in the stretched state. In addition, the 5D controllable conversion of stiffness, transparency, stretchability, color, and shape greatly improves the security and confidentiality of the encoded information inside the gel. This is a successful example of the application of CNC chiral structure in switchable supramolecular network materials. It is believed that the flexible variability and advanced camouflage give the intelligent gel the potential to be used in a wider range of practical scenarios. [ABSTRACT FROM AUTHOR]

Given the widespread prevalence of viruses, there is an escalating demand for antimicrobial composites. Although the composite of dialdehyde cellulose and silver nanoparticles (DAC@Ag1) exhibits excellent antibacterial properties, its weak mechanical characteristics hinder its practical applicability. To address this limitation, cellulose nanofibers (CNFs) were initially ammoniated to yield N-CNF, which was subsequently incorporated into DAC@Ag1 as an enhancer, forming DAC@Ag1/N-CNF. We systematically investigated the optimal amount of N-CNF and characterized the DAC@Ag1/N-CNF using FT-IR, XPS, and XRD analyses to evaluate its additional properties. Notably, the optimal mass ratio of N-CNF to DAC@Ag1 was found to be 5:5, resulting in a substantial enhancement in mechanical properties, with a 139.8% increase in tensile elongation and a 33.1% increase in strength, reaching 10% and 125.24 MPa, respectively, compared to DAC@Ag1 alone. Furthermore, the inhibition zones against Escherichia coli and Staphylococcus aureus were significantly expanded to 7.9 mm and 15.9 mm, respectively, surpassing those of DAC@Ag1 alone by 154.8% and 467.9%, indicating remarkable improvements in antimicrobial efficacy. Mechanism analysis highlighted synergistic effects from chemical covalent bonding and hydrogen bonding in the DAC@Ag1/N-CNF, enhancing the mechanical and antimicrobial properties significantly. The addition of N-CNF markedly augmented the properties of the composite film, thereby facilitating its broader application in the antimicrobial field. [ABSTRACT FROM AUTHOR]

Two types of cellulose nanofibrils (CNFs) were isolated from cotton linter fibers and hardwood fibers through mechanical fibrillation methods. The dialdehyde cellulose nanofibrils (DACNFs) were prepared through the periodate oxidation method, and their morphological and structural properties were investigated. The characteristics of the DACNFs during the concentration process were also explored. The AFM analysis results showed that the mean diameters of wood fiber-based CNFs and cotton fiber-based CNFs were about 52.03 nm and 69.51 nm, respectively. However, the periodate oxidation treatment process obviously reduced the nanofibril size and destroyed the crystalline region of the nanofibrils. Due to the high crystallinity of cotton fibers, the cotton fiber-based DACNFs exhibited a lower aldehyde content and suspension stability compared to the wood fiber-based DACNFs. For the concentration process of the DACNF suspension, the bound water content of the concentrated cotton fiber-based DACNFs was lowered to 0.41 g/g, which indicated that the cotton fiber-based DACNFs could have good redispersibility. Both the wood fiber-based and cotton fiber-based DACNF films showed relatively good transmittance and mechanical strength. In addition, to the cotton fiber-based DACNF films had a very low swelling ratio, and the barrier water vapor and oxygen properties of the redispersed cotton fiber-based DACNF films decreased by very little. In sum, this study has demonstrated that cotton fibers could serve as an effective alternative to wood fibers for preparing CNFs, and that cotton fiber-based DACNFs have huge application prospects in the field of packaging film materials due to their stable properties during the concentration process. [ABSTRACT FROM AUTHOR]

The challenge in energy depletion and environmental pollution urgently demands green and sustainable materials as a new material application platform. Nanocellulose (NC) derived from abundant and renewable resources has been considered as a versatile and sustainable substrate and scaffold to engage various applications. Recently, design and fabricate conductive polymers (CPs)/NC composites as functional electronic devices have received tremendous attention. In this mini review, we start with a brief introduction about the category of nanocellulose, CPs and the preparation strategy of CPs/NC conducive composites followed by discussing the factors that determine the electrical conductivity. Then, we reviewed different CPs/NC composites systems and cited representative electronic application examples including sensors, supercapacitors, lithium-ion batteries. Finally, we proposed current challenges, existing problems and further perspectives and opportunities of CPs/NC conductive composites. [ABSTRACT FROM AUTHOR]

The fast growth of micro-flexible electronic devices has increased the amount of heat generated and electronic waste, which has increased the demand for eco-friendly nanocellulose-based composites with great flame resistance and strong thermal conductivity. Nevertheless, creating appropriate thermally conductive fillers and enhancing the flame retardancy of materials based on nanocellulose remain extremely difficult tasks. This study describes the production of extremely in-plane oriented composite films using TEMPO-oxidized nanocellulose (TOCNF) as the matrix, boron nitride nanosheets (50 wt% BNNS@PDA) as the filler for thermal conductivity, and a small number of phosphorus lignin nanoparticles (2 wt% PL) as an auxiliary filler. First, the orderly organization of thermally conductive fillers in the composite film may be achieved using one-step ball milling, stripping, and non-covalent modification of hexagonal boron nitride, offering an efficient thermal conductivity channel to raise thermal conductivity. After filling in PL (2 wt%), due to the highly compact oriented structure and rich flame-retardant functional groups, the thermal conductivity and flame-retardant properties of the composite film are improved at the same time. The final results demonstrate that the composite film exhibits a high thermal conductivity of 23.49 W mK−1. Compared with a pure nanocellulose film, the TOCNF/BNNS@PDA/PL composite film has a better flame retardant effect and thermal stability. In addition, the composite films show satisfactory flexibility and mechanical properties due to their tight structure and strong interfacial interactions. In conclusion, this work provides a feasible solution for the application of nanocellulose-based thermal conductivity and flame-retardant dual-function composites in thermal management applications for next-generation flexible electronic devices. [ABSTRACT FROM AUTHOR]