A novel photosensitive polyimide based on a polyimide containing the hydroxytriphenylamine structure (HTA-PI) and 2, 3, 4-tris[1-oxo-2-diazonaphthoquinone-4-sulfonyloxy] benzophenone (D4SB) as a photoreactive compound has been developed. The HTAPI was prepared by the ring-opening polyaddition of 4, 4′-hexafluoroisopropylidenebis(phthalic anhydride) (6FDA) and 4,4′-diamino-4″-hydroxytriphenylamine (DHTA), followed by thermal cyclization in refluxing N-methyl-2-pyrrolidone (NMP). The resulting polyimide film showed excellent transparency to 436 nm light. Photosensitive polyimide containing 30 wt% of D4SB showed a sensitivity of 800 mJ cm−2 and a contrast of 0.8 when it was exposed to 436 nm light followed by development with 5% tetramethylammonium hydroxide (TMAH) aqueous solution at 45°C.
Dynamic ionic radius of alkali metal ions in aqueous solution: a pulsed-field gradient NMR study