Kg. Sharp et Mj. Michalczyk, STAR GELS - NEW HYBRID NETWORK MATERIALS FROM POLYFUNCTIONAL SINGLE-COMPONENT PRECURSORS, JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, 8(1-3), 1997, pp. 541-546
New molecular precursors to inorganic/organic hybrid network materials
have been designed and synthesized. The molecules comprise multiple t
rialkoxysilane-terminated arms linked to an organic core. When hydroly
zed, these materials form network structures whose network elements ar
e interconnected with flexible crosslinks. Clear, compliant glasses an
d thick films have been generated from a number of these precursors. T
hey are significantly tougher and less brittle than purely inorganic g
lasses or conventional purely organic thermosetting materials such as
epoxy resins. The gels typically lose all surface-connected porosity d
uring drying. Gelation rates for pure ''star gel'' precursors can be e
xtremely high; the stars can also greatly enhance condensation rates f
or conventional sol-gel systems based on tetraalkoxysilanes.