New photoresist compositions are provided that are useful for immersion lithography. Preferred photoresist compositions of the invention comprise one or more materials that can be substantially non-mixable with a resin component of the resist. Further preferred photoresist compositions of the invention comprise 1) Si substitution, 2) fluorine substitution; 3) hyperbranched polymers; and/or 4) polymeric particles. Particularly preferred photoresists of the invention can exhibit reduced leaching of resist materials into an immersion fluid contacting the resist layer during immersion lithography processing.