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Novel aromatic polyimides containing hydroxytriphenylamine units were prepared from 4,4′-diamino-4″-hydroxytriphenylamine 1 and various aromatic tetracarboxylic dianhydrides 2. The glass transition temperatures ( Tgs) of these polyimides were in the range of 274–388 °C and the 10% weight loss temperatures ( T d10s) were above 462 and 511 °C in air and nitrogen respectively. Polyimide 4f prepared from diamine 1 and 4,4′-hexafluoroisopropylidenebis(phthalic anhydride) (6FDA) was soluble not only in organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 1, 3-dimethyl-2-imidazolidone and dimethyl sulfoxide but also in tetramethylammonium hydroxide aqueous solution. Other resulting polyimides were not soluble in organic solvents. The resulting polyimides 4 possessed Tgs about 20–70 °C higher and poorer solubilities than the previously reported polyimides prepared from 4,4′-diaminotriphenylamine and various aromatic tetracarboxylic dianhydrides. These results indicated that polymer properties such as thermal behaviour and solubilities were influenced by the intermolecular interaction of hydrogen bonding due to hydroxy units.

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.

A main-chain degradable photosensitive polyimide containing an acetal structure which degrades by the action of acid coming from a photoacid generator has been developed. Polyimides 4 were prepared by the reaction of bis(4-aminophenoxy)methane 1 and various tetracarboxylic anhydrides 2, followed by thermal treatment. In the resulting polyimides 4, 4f filmderivedfrom 4,4′-hexafluoroisopropylidenebis(phthalicanhydride)(6FDA)and 1 showedgood solubility in organic solvents and transparency to UV light. The acid-catalysed degradation reaction was confirmed by the model imide compound in the presence of p-toluenesulfonic acid. The system of the polyimide 4f containing 30 wt% of diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS), which is a photoacid generator (PAG) showed a sensitivity of 150 mJ cm−2 with 436 nm light, when it was post-exposure baked at 140°C for 30 min, followed by development with 5% tetramethylammonium hydroxide solution at 45°C.

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