Surface Properties of Silica–MWCNTs/PDMS Composite Coatings Deposited on Plasma Activated Glass Supports

Michał Chodkowski,Dariusz Sternik,Iryna Ya Sulym,Konrad Terpiłowski

doi:10.3390/app11199256

Abstract

In this paper, we focus on fabrication and physicochemical properties investigations of silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) composite coatings deposited on the glass supports activated by cold plasma. Air or argon was used as the carrier gas in the plasma process. Multiwalled carbon nanotubes were modified with poly(dimethylsiloxane) in order to impart their hydrophobicity. The silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) nanocomposite was synthesized using the sol–gel technique with acid-assisted tetraethyl orthosilicate hydrolysis. The stability and the zeta potential of the obtained suspension were evaluated. Then, the product was dried and used as a filler in another sol–gel process, which led to the coating application via the dip-coating method. The substrates were exposed to the hexamethyldisilazane vapors in order to improve their hydrophobicity. The obtained surfaces were characterized by the wettability measurements and surface free energy determination as well as optical profilometry, scanning electron microscopy, and transmittance measurements. In addition, the thermal analyses of the carbon nanotubes as well as coatings were made. It was found that rough and hydrophobic coatings were obtained with a high transmittance in the visible range. They are characterized by the water contact angle larger than 90 degrees and the transmission at the level of 95%. The X-ray diffraction studies as well as scanning electron microscopy images confirmed the chemical and structural compositions of the coatings. They are thermally stable at the temperature up to 250 °C. Moreover, the thermal analysis showed that the obtained composite material has greater thermal resistance than the pure nanotubes.

Highlights

Silica materials are a large group of functional materials with a wide range of applications [1]
The transmission along the entire length of the flask was equal to zero because of the formation of an opaque, black product
The silica–multiwalled carbon nanotubes (MWCNTs)/PDMS composite coatings on the glass supports modified with cold plasma were fabricated using the quick and simple sol–gel method

Summary

Introduction

Silica materials are a large group of functional materials with a wide range of applications [1]. The final properties of the product depend on the process parameters such as type of precursor and solvent, catalyst, or temperature. This makes it an effective, simple, and cheap technology characterized by many advantages [2]. Silica coatings can be doped with various fillers or modifiers in order to improve or change their properties When the two constituents are at the nanometer or molecular level, this is a hybrid material [5] This combination, consisting of organic and inorganic constituents, makes an interesting material with specific physical, thermal, optical, electrical, and mechanical properties that are promising for various applications [6,7]

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