Synthesis of optically active chiral mesoporous molybdenum carbide film

ACS Appl. Mater. Interfaces

Wang

et al. 2021

Self Cite

Cellulose nanocrystals (CNCs) are powerful photonic building blocks for the fabrication of biosourced colored films. A combination of the advantages of self-assembled CNCs and multiple templating agents offers access to the development of novel physicochemical sensors, structural coatings, and optic devices. However, due to the inherent brittleness and water instability of CNCderived materials, their further applications are widely questionable and restrictive. Here, a soft polymer of poly(vinyl alcohol) (PVA) was introduced into the rigid CNC system to balance molecular interactions, whereafter two hard/soft nanocomposites were fastened through a cross-linking reaction of glutaraldehyde (GA), resulting in a highly flexible, water-stable, and chiral nematic CNC composite film through an evaporation-induced self-assembly technique. For a 1.5 wt % GA-cross-linked 70 wt % CNC loading film, its treatment with harsh hydrophilic exposure (soaking in a strong acid, strong base, and seawater) and various organic solvents show exceptional solvent-resistant abilities. Furthermore, the film can even withstand a weight of 167 g cm −2 without failure, which is a highly stiff and durable character. Importantly, the film remains a highly ordered chiral nematic organization, being able to act as a highly transparent substrate for selective reflection of left-handed circularly polarized light, preparing fully covered and patterned full-color coatings on various substrates. Our work paves the way for applications in low-cost, durable, and photonic cellulosic coatings.

Section: Results and Discussionmentioning

confidence: 61%

Section: ■ Results and Discussionmentioning

confidence: 99%

Highly Strong and Solvent-Resistant Cellulose Nanocrystal Photonic Films for Optical Coatings

ACS Appl. Mater. Interfaces

Wang

et al. 2021

Self Cite

“…Cellulose nanocrystals (CNCs) are well-studied biomass nanoparticles due to their high annual availability, renewable properties, low cost, and excellent mechanical and optical properties (Foster et al 2018). They have been investigated for tissue engineering (Sato et al 2021), food packaging (Rader et al 2021), optically active films (Zhang et al 2021), and other applications (Li et al 2018a).…”

Section: Introductionmentioning

confidence: 99%

Preparation, properties, and mechanism of anionic and cationic cellulose nanocrystals/waterborne polyurethane composite films

Bai

et al. 2022

BioRes

Three kinds of cellulose nanocrystals (CNCs) were added into waterborne polyurethane (WPU) and nanocomposite films that were prepared by solution casting. The influence of different ionic function groups on microstructure and properties of composite films was investigated. Compared with sulfated CNCs (SCNCs) and TEMPO oxidized CNCs (TOCNCs), FE-SEM images showed that cationized CNCs (CaCNCs) had better dispersion in composite films. The thermal decomposition of these composite films was delayed by 15 °C compared with pure WPU film. The tensile strength and fracture work of CaCNC/WPU composite film increased by 11.9% and 8.4%, respectively. The light transmittance of CaCNC/WPU composite film was highest among the 3 composite films, but its oxygen permeability was the lowest. In sum, the composite film with CaCNCs had optimal strength, toughness, light transmittance, and oxygen barrier properties, which is consistent with good compatibility of the two components and densest structure observed in SEM. There may be an ionic attraction and hydrogen bonds of CaCNCs and WPU in the composite film. The composite films are expected to have applications in food packaging, furniture coatings, and biomedical fields.

“…Cellulose nanocrystals (CNCs) have become the most active biomass nanoparticles in recent 20 years due to their high annual availability, renewable properties, low cost and excellent mechanical and optical properties (Foster et al 2018). It has been investigated for tissue engineering (Sato et al 2021), food packaging (Rader et al 2021), optically active lms (Zhang et al 2021), and so on (Li et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Preparation, Properties and Mechanism of Anionic and Cationic CNC/WPU Composite Films

Bai

et al. 2021

Preprint

Three kinds of cellulose nanocrystals (CNCs) were added into waterborne polyurethane (WPU), and nanocomposite films were prepared by solution casting method. The influence of different ionic function groups on microstructure and properties of composite films was investigated, and interaction mechanism between these two components was analyzed. Results show that thermal stability of these composite films are improved by 15℃. Compared with sulfated CNCs （SCNCs） and TEMPO oxidized CNCs (TOCNCs), FE-SEM results prove that cationized CNCs (CaCNCs) have better dispersion in composite films. In addition, fracture surface did not display large cavities, which indicates the interface binding force between WPU and CaCNCs is stronger. The tensile strength and fracture work of CaCNC/WPU composite film increase by 11.9% and by 8.4%, respectively. The oxygen permeability of CaCNC/WPU composite film is the lowest in these composite films, which is 5.00 cm3•cm (cm2•s•Pa)-1. Water vapor permeability of composite films may have a close positive correlation with their hygroscopicity. In all, composite film with CaCNCs has optimal strength, toughness, light transmittance and oxygen barrier properties. There may be opposite ion attraction superimposed hydrogen bond between CaCNCs and WPU in the composite film. The composite films are expected to have applications in food packaging, furniture coatings and biomedical applications.