contacting {HEAD ~ the polyimide surface} with an aqueous solution of nitric acid having {TAIL ~ a concentration} of about 35 to about 70% by weight or an aqueous solution of hydrochloric acid having a concentration of about 10 to about 38% by weight 
contacting { HEAD ~ the polyimide surface } with an aqueous solution of nitric acid having { TAIL ~ a concentration } of about 35 to about 70 % by weight or an aqueous solution of hydrochloric acid having a concentration of about 10 to about 38 % by weight
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH