E. Stathatos et al., Structural study of hybrid organic/inorganic polymer gels using time-resolved fluorescence probing, LANGMUIR, 16(23), 2000, pp. 8672-8676
Thin films made of hybrid organic/inorganic polymers, synthesized through t
he sol-gel method and composed of silica with grafted poly(ethylene oxide)
or poly(propylene oxide) chains, are studied by time-resolved fluorescence-
probing analysis. The fluorescence-probing technique is employed both to st
ructurally characterize these nanoheterogeneous materials and to demonstrat
e the capacity of this technique to detect important differences in materia
ls having approximately the same chemical structure. It is found that the f
ilms consist of interpenetrating networks of organic and inorganic domains
constituting two distinguishable subphases, an organic and an inorganic one
. The volume fraction of the organic phase is larger than that of the inorg
anic phase, and it increases with increasing poly(ethylene oxide) or poly(p
ropylene oxide) chain length. In addition, hydrophobic interactions tend to
organize the organic domain, forming organic clusters that can accommodate
hydrophobic probes. This is particularly true for large polyether chains.