I am not in a position to judge the merits of Research Disclosures. I know that they are an organization that will publish Research and allow others to obtain copies of the publication for a fee. Kodak used their service for years, and in several my co-inventors and I have disclosed polymeric peptizing agents and vehicles.
Defensive publications are issued by the US Patent Office. They are very difficult to obtain. They are noted by having a "T" in front of their name (IIRC). The RDs are hard to get at and you are charged, the DPs are almost impossible to find on the Patent Office web site, but they do refer to them in the advanced search.
I have no idea as to cost, as I have no interest in getting personal copies of my own work and paying for it. Sorry.
What comes to mind is the Silver Behenate thermally processed material that was offered by EK several years back. The emulsion was coated from an organic solvent using a synthetic polymer base. It was not hardened AFAIK as it never was wet processed but rather was heat processed.