Forming patterns using thiosulfate polymer compositions

A method of forming a pattern in a polymeric composition, the method comprising:

• providing a polymeric layer comprising a non-crosslinked thiosulfate polymer and an electron-accepting photosensitizer component (PS),
• photochemically reacting the non-crosslinked thiosulfate polymer to provide a crosslinked polymer having disulfide groups in a predetermined pattern in the polymeric layer, leaving non-crosslinked thiosulfate polymer in area(s) of the polymeric layer outside of the predetermined pattern,
• optionally washing the polymeric layer to remove the non-crosslinked thiosulfate polymer while leaving the crosslinked polymer in the predetermined pattern, and
• either:
• (i) treating the crosslinked polymer with a disulfide-reactive material, or
• (ii) when the polymeric layer further comprises a redox active metal ion, treating the predetermined pattern with a metal ion that is capable of reacting with the redox active metal ion,
• wherein the excitation energy, EPS*, of the electron-accepting photosensitizer component (PS) satisfies the following Equation 2:
• EPS*≧ERox−EPSred Equation 2
• in which ERox represents the oxidation potential of reactant thiosulfate moiety (R) in the non-crosslinked thiosulfate polymer and EPSred represents the reduction potential of the electron-accepting photosensitizer component (PS).