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Title: Adhesion enhancement of sol–gel coating on polycarbonate by heated impregnation treatment
Authors: Wu, Linda Y. L.
Boon, L.
Zeng, X. T.
Chen, Zhong
Keywords: DRNTU::Engineering::Materials::Microelectronics and semiconductor materials::Thin films
Issue Date: 2009
Source: Wu, L. Y. L. , Boon, L., Chen, Z., & Zeng, X. T. (2009). Adhesion enhancement of sol–gel coating on polycarbonate by heated impregnation treatment. Thin Solid Films, 517(17), 4850-4856.
Series/Report no.: Thin solid films
Abstract: The main limitation in using coated plastics for optical components, electronic applications and display systems is the softness of the substrate surfaces, which is responsible for the low impact and abrasion resistance and weak adhesion between the coating and the substrate. In this paper, we report a new strategy for surface pre-treatment of plastics using heated vacuum equipment and sol–gel materials to provide both chemical bonds and penetrated hard layer into the plastic surface to increase the overall performance of the coated plastic components. The heated vacuum treatment process involves: (1) surface cleaning and pore opening by heating and vacuum conditions, (2) impregnation of hydrolyzed hybrid precursor into polymer substrate under pressure and elevated temperature, (3) aminolysis of diffused precursor with surface to form chemical bonds and hardened surface layer, (4) formation of chemical bonds at treated surface with sol–gel hard coating. An impregnation depth of 1.5 µm was detected. Water contact angle dropped to below 40° and roughness increased after treatment. These provided better adhesion by increased wettability and contact area. Much increased nanoindentation hardness and Young's modulus after impregnation provided a gradient in mechanical properties between soft substrate and hard sol–gel coating. The hardened substrate delays the plastic deformation in substrate during pencil scratch test, thereby preventing early gouge failure. Both the better adhesion and the delayed gouge failure contributed to the increased scratch resistance from 6B to 8H after sol–gel coating.
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2009.03.086
Rights: © 2009 Elsevier B.V. This is the author created version of a work that has been peer reviewed and accepted for publication by Thin Solid Films, Elsevier B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [].
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:MSE Journal Articles

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