Electroless plating is similar to electroplating. The only difference is electroless plating does not require external biasing. Instead, it requires a reducing agent (some chemical). In this regard, it seems not possible to deposit other materials than metals or alloy via electroless plating. 

Best,

Chandan 

Some papers describe of electroless coating of polymeric materials like PTFE in combination with metals like Ni. But i am not aware of coating only non metallic coating on substrates through electroless coating. 

Thank you both; I thought this was the case but just wanted to check I hadn't missed any literature.

As your material is not known to us, I have a blind suggestion.

You probably may try with chemical bath deposition method. 

You can go through this paper "Ink-Jet Printing of Catalyst Patterns for Electroless Metal Deposition". May be helpful for your research work.

You can electroless coat a non-metal, though it's not often done. The only practical applications I can think of involve lead. As an example, if you have lead pipes or pipes soldered with lead, they will become coated with lead-oxides and over time this lead will leach into the drinking water. You can add chlorine or hypochlorite to the drinking water, you form a coat of insoluble lead chloride on the surface of the pipe, and soluble, non-lead oxides in solution. 

thank you all for taking the time to respond. I'll take a look into the options you suggest although I think they'll all be unsuitable.

I think it is not suitable to use electroless plating to deposit a non-metal and can be used spraying method or coating method for non-metal.