Cross-Linked and Surface-Modified Cellulose Acetate as a Cover Layer for Paper-Based Electrochromic Devices

Photopolymerization Pattern of New Methacrylate Cellulose Acetate Derivatives

Polymeric photocrosslinked networks, of particular interest in the design of materials with targeted characteristics, can be easily prepared by grafting light-sensitive moieties, such as methacrylates, on polymeric chains and, after photochemical reactions, provide materials with multiple applications via photopolymerization. In this work, photopolymerizable urethane-methacrylate sequences were attached to free hydroxyl units of cellulose acetate chains in various proportions (functionalization degree from 5 to 100%) to study the properties of the resulting macromolecules and the influence of the cellulosic material structure on the double bond conversion degree. Additionally, to manipulate the properties of the photocured systems, the methacrylate-functionalized cellulose acetate derivatives were mixed with low molecular weight dimethacrylate derivatives (containing castor oil and polypropylene glycol flexible chains), and the influence of UV-curable composition on the photopolymerization parameters being studied. The achieved data reveal that the addition of dimethacrylate comonomers augmented the polymerization rates and conversion degrees, leading to polymer networks with various microstructures.

Regeneration and modification of cellulose acetate from cigarette waste: Biomedical potential by encapsulation of tetracycline hydrochloride

Cigarette waste are pervasive litter on Earth, posing a major threat to organisms and ecosystems. However, these waste contain cellulose acetate (CA) and can be recycled, transforming into raw materials for new products. Polymers like CA can be used in biomedical applications as drug carriers and scaffolds for drug release. In this study, cigarette filters waste was collected, recycled and used for fabricating the nanofibrous membrane of cellulose acetate nanofibers (CFCA) through electrospinning technique. Tetracycline hydrochloride (TC) was encapsulated in the nanofibers to prevent bacterial infections. Various analyses were conducted: Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction Analysis (XRD) and Thermogravimetric analysis (TGA). CA and CFCA exhibited high water uptake properties and exhibited similar breaking stress and strain values. Both CA and CFCA effectively acted as stable drug carriers, with sustained in vitro drug release. Antibacterial activity was demonstrated by the drug-loaded CA and CFCA nanofibers against, Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. Based on their cytotoxicity evaluations on mouse fibroblast cells (L929), CA and CFCA fibrous mats demonstrated no cytotoxicity and similar cell viability results. Consequently, the TC-loaded nanofibers made from CA and CFCA exhibited suitable properties for wound healing applications.

Cellulose-based slippery covalently attached liquid surfaces for synergistic rain and solar energy harvesting

For solar cell-triboelectric nanogenerator (TENG) integration, the design of the solid substrate for the TENG device becomes one of the challenges. The TENG needs to have superior contact electrification properties and be transparent so as to ensure light transmittance. Here, by spontaneous polymerization of dichlorodimethylsilane in the absence of any toxic solvent, we have fabricated a controllable liquid-like polydimethylsiloxane brush, featuring hydrophobicity, long-term stability, robustness, and UV resistance. A drop of liquid slides off at tilt angles below 5° and there is dynamic contact angle hysteresis of no more than 10° that can provide strong self-cleaning ability to the solid substrate. This recipe is also applicable to surfaces composed of hydroxyl group-rich cellulose-based surfaces, such as flexible cellulose acetate film (CAF). Importantly, PDMS@CAF, a flexible, transparent, and self-cleaning TENG device with a light transmission rate of 99% or more, was prepared using a conductive polymer film of PH 1000. The hybrid energy harvesting system formed by the combination of this transparent TENG equipped with solar cells is promising for harvesting energy from the environment in different weather conditions.