Durable Antifog Films from Layer-by-Layer Molecularly Blended Hydrophilic Polysaccharides

Abstract

Mechanically durable, long-lasting antifog coatings based on polysaccharides were developed using a layer-by-layer (LBL) assembly process. The unique properties of these coatings are a result of a molecular-level blending of the polysaccharides, with multilayers containing chitosan and carboxymethyl cellulose providing the best overall properties. The antifog properties resulted from a strong interaction between the polar and H-bonding elements of the assembled polymers and water molecules and the concomitant formation of thin films of water. Environmental scanning electron microscopy (ESEM) studies confirmed that fogging coatings are decorated with light scattering, micrometer-sized droplets of water whereas antifogging coatings remain droplet free. To improve the mechanical durability of the multilayer films on substrates, the surface was modified via self-assembly of epoxy-functionalized silane molecules. Cross-linking chemistry was then applied to improve the mechanical robustness of the LBL films on various surfaces. These films were characterized using several techniques: optical profilometery (PL), spectroscopic ellipsometry (EL), contact angle goniometry (CA), and atomic force microscopy (AFM). The antifog properties of the films were evaluated by several tests under different environmental conditions. This work demonstrates that the unique water-adsorbing properties of polysaccharides can be exploited to create permanent antifog properties, which may be useful for various applications.

Fogging Control on LDPE/EVA Coextruded Films: Wettability Behavior and Its Correlation with Electric Performance

“…Several hydrophilic compounds have been developed as non-migratory agents, including silicon-based molecules, metallic oxide nano-particles and blends with hydrophilic polymers, among others [1,6,7,8,9,10,11,12]. Current technology that increases the wettability of non-polar polymers using surfactants is preferred by the industry, because it implies minor technological difficulties and lower costs without alterations in the bulk properties of the polyolefin [13,14]. However, its performance is limited to the migration of the additive from the inside of the polymeric matrix to the surface in contact with water and also to the retention of released amphiphilic molecules [15].…”

Study of Hydrophilic Electrospun Nanofiber Membranes for Filtration of Micro and Nanosize Suspended Particles

“…The polyvinyl chloride (PVC) nanomembrane exhibits a hydrophobic nature and cannot be used easily for the filtration process. The wettability of the membrane surface depends on its microstructure and chemical nature; however, surface modification can be applied on the membrane to increase its hydrophilicity [13,14,15,16,17]. In this study, water soluble polyvinylpyrrolidone (PVP) was added into PVC at different percentages (2%, 3%, 4%, and 5%) and then electrospun to produce highly hydrophilic nanofiber membranes.…”

Fabrication of the durable low refractive index thin film with chitin-nanofiber by LBL method

“…Antifogging films that were fabricated for the lenses in safety goggles have been reported. 16 In that study, the refractive index was 1.54, and the thin films were durable. However, the transmittance of the fabricated films was very similar to that of glass substrates.…”