Dear sir,

For depositing DLC thin films on temperature sensitive substrates, i think PECVD is a good method to employ. 

yes PECVD with 13,5 MHz is a good choice up to 1 square meter.. if bigger, that may change depending on your requirements of thickness homogeneity.

Germans were looking for 3x6 meters samples.. no idea, if ever realised.

for 2 or 3 millions Euros, I would build you a machine.. I am kidding, but for sure this would be a minimum.

For large area deposition of DLC you could also use the inverted fireball method my colleagues and I developed at the university of Graz.

With this the area of your substrate can be scaled ad infinitum (theoretically).

Dear Dr Rao, Dr Alberts and Dr Gruenwald,

Thank you for your valuable comments. Are there any reports or published work on DLC  film growth/coating on the polymer/plastic substrates? Is it physically possible to realize reliable DLC coating on the polymer/plastic surface without considerable deformations, as plasma coating generally needs high substrate temperature? Is there any other cheaper technology/ way to realize reliable DLC on plastic/polymer surfaces to deal with cleaning issues and longer life of the polymer/plastic bathroom wall, tub and floor? With many thanks once again for your feedback and warm regards,

Not so many, usually DLC or diamond coating processes require substrate temperatures in the order of several 100 °C. However, there is for example this paper on DLC coatings on PET:

http://www.sciencedirect.com/science/article/pii/S0040609005014616

Coating large area parts with an industrial-scale process must respond to several requirements, and cost is considered as one of the most important, specially when you have to coat consumable or relatively low-cost goods as in your case.

Of course, technical requirements are quite important as well. As a matter of facts, the chosen process must leave the underlying part unmodified in its main characteristics, and homogeneity of the coating is often a must (within specified limits of acceptance. The latter factor means that you must choose a coating process suited for non-planar surfaces.

Just the few points above are enaugh, in my opinion, to say that a low-cost, flexible, high-rate process would not be better... it would be a must for an economically viable solution.

Spraying (cold or moderately worm one) seems to be a solution inasmuch as you may use proper dispersion of nano- or micro-particles of a DLC material in a compatible solvent... more or less like a paint.

Diamond nano- and submicro- particles in powder form are already commercialized by some important manufacturers, and such powders may be dispersed in a proper solvent and sprayed on your surfaces. But the cost is the material... not the spraying equipment.

Recently investigations of DLC nanoparticle formation in a reactive solvent like benzene have been carried out... but benzene is not a liquid easy to be managed in spraying applications.

Definitively, I suggest you go deeper inside the possibility of using (at industrial scale level) Spraying as a method and nanodiamond powders (after accurate examination of the large scale costs), or try looking for manufacturers of DLC nano- or micro-particle powders

DLC has many many different forms.. depending on your application you can choose the quality of the dlc needed. then you may choose the right equipment for it.  at last you may find it economical or not.

you will not find one machine capable of delivering the right solution for two different applications.  one sample/application will have its optimal process.. anything else needs to be restarted from scratch.

spraying can be perfect for some cases.

Dear Dr Curro, Dr Gruenwald, Dr Alberts,

Thank you for your very interesting and valuable comments/feedback. DLC coating on wafer level flat surfaces are often reported in the literature. However, when it comes to relatively rough surfaces like polymers used for house hold items in kitchen and bathrooms, their relatively rough surface might need not only larger quantity of (expensive?) DLC material but also film/layer of sub micron (preferably less than 100 nm, i.e., 50+/- 50 nm?) thickness might need very special approach/care (or may be nearly impossible?) when spray technique is considered. By the way, is there anyone or venture company interested in such process and has experience in DLC coating where it could be consulted or approached for a feasibility test possibility. With warm regards,