Diamond growth on copper rods from polymer composite nanofibres

Highlights: • Diamond growth homogeneity on vertically positioned substrates exposed to various CH₄/CO₂/H₂ gas mixtures. • Description of the polyvinyl alcohol (PVA) fibres transformation according to the applied pre-treatment step. • Preparation of adherent continuous diamond film on copper rod by using PVA composite nanofibre textile employed as the nucleation/seeding layer. • Proposing of the schematic model of the diamond film formation on copper with the assistance of PVA textile. - Abstract: The potential uses of diamond films can be found in a diverse range of industrial applications. However, deposition of diamond films onto some foreign materials is still not a simple task. Here we present the growth of adherent diamond films on copper rods with the focus on substrate pre-treatment by polyvinyl alcohol composite nanofibres. The primary role of the polymer fibres substantially act as a carbon source which enhances the diamond nucleation and accelerates a homogenous CVD growth. Diamond growth was carried out in pulsed linear antenna microwave chemical vapour deposition system, which is characterized by cold plasma due to larger distance of hot plasma region from the substrate, at various gas compositions. The large distance between plasma source and the substrate holder also allows the uniform deposition of diamond on a large number of substrates with complex geometry (3D objects) as well as for the vertically positioned substrates. Moreover, the inhomogeneity in diamond film thickness deposited on vertically positioned substrates was suppressed by using polyvinyl alcohol nanofibre textile. Combination of PVA polymer fibres use together with this unique deposition system leads to a successful overcoating of the copper rods by continuous diamond film without the film cracking or delamination. We propose that the sequence of plasma-chemical reactions enhances the transformation of certain number of carbon atoms into the sp³-bonded form which further are stabilized by atomic hydrogen coming from plasma