Plasma-Induced Polymeric Coatings

Anand, V and Thomas, R and Thulasi Raman, KH and Gowravaram, MR (2018) Plasma-Induced Polymeric Coatings. [Book Chapter]

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Abstract

The formation of thin film coatings of polymers in glow discharge systems was recognized as early as the 19th century. However, they were considered as by-products of electrical discharges and hence little attention was paid. Only the period after 1950s saw their renaissance, as practical ways to make special coatings on metals. Since then, much research has been done in plasma induced polymers and interesting, as well as, industry relevant applications have been identified for polymers deposited using plasmas because of their flawless thin film structure, excellent adhesion to the substrate, chemical inertness and low dielectric constant. In this chapter the significance of Plasma Induced polymer coatings is presented with more emphasis on the process aspects, general methods of characterization of these polymers and application of such polymers in super hard coatings. In the first part, a clear distinction has been made between Plasma Polymerized and Plasma Induced Polymerized coatings based on the mechanism of the process. The processing parameters that greatly influence the properties of such coatings are considered. A definition for the rate of deposition based on these process parameters has been established. This section ends with the most commonly used monomer materials in plasma induced polymerization systems. Special case studies on Atmospheric pressure plasma Vs Low pressure plasma treatment of polymer surface and on the plasma treatment of Polydimethylsiloxane (PDMS) surfaces for bio applications are considered. Inorganic hard coatings are widely used in many industries and these are basically transition metal nitrides and carbides and their combination. Hardness of these compounds ranges form 20-40GPa. The hardness and stiffness (elastic modulus) are completely governed by the nature of bonding, distance between the two atoms and etc., Hardness of the super hard coatings is above 40GPa, and this hardness is achieved using nano size and composite effects methods and these coatings are widely used surface engineering industries. Polymer based coatings are also gaining momentum to replace some of the inorganic hard coatings. At present polymer coatings are having lower hardness compare with inorganic coatings and the hardness range of 1-3GPa. The reason for lower hardness in the polymer coatings is predominant contribution from sp2 hybridization. To enhance the polymer coating hardness, the polymer should be rich in sp3 hybridization and incorporation of foreign materials into the polymer matrix which is having higher degree of covalent and ionic nature. Plasma enhanced metal organic chemical vapour deposition (MOCVD) and physical or chemical sputtering of solid metal target along with the plasma polymerization are the two strategies of obtaining the nano particle or nanocomposites embedded polymer films. These polymers can be utilized for many applications such as optical coatings, protective films, biomedical materials etc. Details of plasma techniques used to produce nano composites especially using microwave and RF plasmas are discussed here.

Item Type:	Book Chapter
Publication:	Non-Thermal Plasma Technology for Polymeric Materials: Applications in Composites, Nanostructured Materials, and Biomedical Fields
Publisher:	Elsevier
Additional Information:	The copyright for this article belongs to the Elsevier Inc.
Keywords:	Metal/metal oxide embedded plasma polymers; Nanocomposites; Plasma induced polymerization; Plasma polymerization; Polymer superhard coatings; Rate of polymerization
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	14 Aug 2022 05:57
Last Modified:	14 Aug 2022 05:57
URI:	https://eprints.iisc.ac.in/id/eprint/75734

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