In this paper, we report that the interfacial interaction in polyimide (PI)
/silica hybrid composites can be characterized by a fluorescence spectrosco
py. We found that silica shows different effects on the fluorescence behavi
or of polyimide based on biphenyltetracarboximide (BPDA) depending on the t
ype of diamine, that is, whether it is oxydiphenyldiamine (ODA) or phenylen
ediamine (PDA). The polyimide/silica hybrid composite films were prepared b
y thermal imidization and sol-gel method from tetraethoxy silane (TEOS). Fo
r the polyamic acid (PAA)/TEOS solutions, the interfacial interaction was d
iscussed in terms of the intermolecular hydrogen bonding between PAA and Si
(OH)(4) or complexation between a solvent, N-methylpyrrolidinone (NMP), and
PAA. Significant changes in the fluorescence wavelength as well as intensi
ty were observed by the presence of silica particles in the. case of BPDA-P
DA/silica composite films as compared to the case of BPDA-ODA/silica compos
ite films. We found that silica has some interaction with BPDA-PDA but no i
nteraction with BPDA-ODA in PI films. The interfacial interaction between s
ilica and BPDA-PDA or BPDA-ODA was explained by different electron-donating
strength of the diamines, here, PDA and ODA.