INTRODUCTION OF FUNCTIONAL-GROUPS INTO POLYMER-FILMS VIA DEEP-UV PHOTOLYSIS OR ELECTRON-BEAM LITHOGRAPHY - MODIFICATION OF POLYSTYRENE AND POLY(3-OCTYLTHIOPHENE) BY A FUNCTIONALIZED PERFLUOROPHENYL AZIDE

A general method for the covalent attachment of functional groups to polymer films is described. The key step likely involves a C-H bond insertion reaction of a highly reactive nitrene intermediate derived from a functionalized perfluorophenyl azide (PFPA). The nitrene can be generated either by photolysis or during electron-beam lithography. Since a N-hydroxysuccinimide (NHS) active ester group is present elsewhere in the nitrene intermediate, this group also becomes attached covalently to the polymer and is capable of further reaction with a variety of reagents containing an ammo group by way of amide formation. The methodology is illustrated by the following examples: Photolysis of a polystyrene (PS) or poly(3-octylthiophene) (P3OT) film containing 8-10 wt % of NHS-functionalized PFPA (1) resulted in the installment of the NHS groups into the polymers. Reaction of the NHS modified polymer films with amino azide 3 resulted in the introduction of azide groups into the polymers as determined by IR spectroscopy. Alternatively, electron-beam lithography of PS or P3OT films containing 1 resulted in both the introduction of NHS groups and the cross-linking of the polymers in a single step. Micron-size patterns incorporating the NHS functional groups could be produced. Treatment with amino fluorescein 7 resulted in the covalent attachment of fluorescent groups into the polymer structure.