Novel inorganic morphologies formed in polyimide/silica hybrid films

2-(4-Aminophenyl)-5-aminobenzimidazole was used to prepare polyimide/silica hybrid films via sol–gel process. At 40 wt.% silica content, hybrid films were still translucent. No noticeable silica particle has been observed. Unexpectedly, after treating at 800 °C, novel morphologies of silica were observed on the surface of inorganic films, which changed from homogeneous to sea-island and to co-continuous structure with increasing silica content in the matrix. Hydrogen bonding between NH in imidazole and silanol group results that silica tends to linear structures, which is considered as the main reason for this morphological change.

Graphical abstractNo obvious particles were found in PI/SiO2 hybrid films using PABZ. After calcinations, novel morphologies were found. There were only silicon and oxygen left, generally, there out to be spherical particles (d, PDA-20, 60000×), actually, two phases were observed and morphologies changed from homogeneous (a, PABZ-20, 700×) to sea-island (b, PABZ-30, 700×) and to co-continuous structure (c, PABZ-40, 700×).Figure optionsDownload full-size imageDownload as PowerPoint slide