Molecularly blended natural and synthetic polymer coatings for antifog applications prepared by layer-by-layer deposition

PMSE 281

Nurxat Nuraje, nurxat@mit.edu1, Girma Endale1, Robert E. Cohen2, and Michael Rubner, rubner@mit.edu1. (1) Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, (2) Department of Chemical Engineering, Massachusetts Institute of Technology, MA
Fogging is a well-known phenomenon in medical devices, vehicle windows, airplane windshields, optical wear (eye glasses, goggles, and face shields), binoculars and other optical instruments, etc. In this paper, we describe a new type of hydrophilic coating that can be applied to any surface to produce a long-lasting, durable anti-fog effect. The coating achieves its unique properties as a result of the creation of a molecular-level blend of two hydrophilic polymers including at least one natural polymer. The coating is assembled using a layer-by-layer assembly process. Natural polymers such as chitosan or carboxyl methyl cellulose have more oxygen and hydroxyl groups in their backbone and side groups compared to typical synthetic polyelectrolytes (PE) such as poly(acrylic acid) (PAA), and poly(allyamine) (PAH). Furthermore, to examine the importance of hydrophilicity of the coating on anti-fog properties, poly(ethylene oxide) grafted poly(acrylic acid) copolymers were synthesized with variable amounts of poly(ethylene oxide) in the copolymers, and then these copolymers were assembled with chitosan on glass and polycarbonate substrates. The anti-fog properties of these various multilayer coatings are discussed. The films were characterized by profilometry, spectroscopic ellipsometry, contact angle measurement , and atomic force microscopy. The anti-fog properties of the films were evaluated by an aspiration test, optical test and humid chamber test.