Sol-gel derived compositions
Disclosed are sol gel derived materials obtained from at least one first precursor and at least one second precursor, as well as sol gel derived compositions containing a plurality of alkylsiloxy substituents obtained from such sol-gel derived materials.
1. A sol-gel composition obtained from at least a first alkoxysilane precursor and a second alkoxysilane precursor, where at least the second alkoxysilane precursor is a bis(trialkoxysilylalkyl)benzene that is 1,4-bis(trimethoxysilylmethyl)benzene (BTB), bis(triethoxysilylethyl)benzene (BTEB), or a mixture thereof, and where the sol-gel composition is swellable to at least 1.5 times its dry volume, when placed in excess acetone.
2. The sol-gel composition of claim 1 wherein
the first alkoxysilane precursor has the formula:
(RO) x (R 2 ) y Si((R 1 )Si(R 2 ) y (OR) x ) z (1)
where x is 2, 3 or 4, y is 0, 1 or 2 and z is 0 or 1, where the sum of x+y+z is 4, and where each R is independently a C 1 to C 6 alkyl, R 1 is an alkyl or aromatic bridging group and each R 2 is individually an organic group and
the second alkoxysilane precursor has the formula:
(RO) 3 Si—(CH 2 ) n —Ar—(CH 2 ) m —Si—(OR) 3 (2)
where n and m are individually an integer from 1 to 8, Ar is a single-, fused-, or poly-aromatic ring, and each R is independently an alkyl group as defined above; and
wherein the second alkoxysilane precursor is 1,4-bis(trimethoxysilylmethyl) benzene (BTB), bis(triethoxysilylethyl)benzene (BTEB), or a mixture thereof.
3. The sol-gel composition of claim 2 , wherein the amount of first alkoxysilane precursor to second alkoxysilane precursor is from about 5:95 mol:mol to about 60:40 mol:mol.
4. The sol-gel composition of claim 2 , wherein the amount of first alkoxysilane precursor to second alkoxysilane precursor is from about 20:80 mol:mol to about 50:50 mol:mol.
5. The sol-gel composition of claim 2 , wherein R is methyl or ethyl.
6. The sol-gel composition of claim 2 , wherein each R 2 is independently an aliphatic or non-aliphatic hydrocarbon containing up to about 30 carbons.
7. The sol-gel composition of claim 6 , wherein the hydrocarbon is a straight-chain hydrocarbon, a branched-chain hydrocarbon, a cyclic hydrocarbon or an aromatic hydrocarbon.
8. The sol-gel composition of claim 1 , wherein the sol-gel composition contains a plurality of alkylsiloxy substituents.
9. The sol-gel composition of claim 8 , wherein each of the alkylsiloxy substituents correspond to the formula:
—(O) w —Si—(R 3 ) 4-w (3)
where R 3 is independently a hydrocarbon containing up to about 2 carbons, and w is an integer from 1 to 3.
10. The sol-gel composition of claim 9 , wherein each of the alklysiloxy substituents include at least one heteroatom selected from sulfur, oxygen, nitrogen, phosphorous, a halogen, or a combination thereof.
11. The sol-gel composition of claim 1 , wherein the first precursor is tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysiliane, aminopropyl-trimethoxysilane, 1,4-bis(triethoxysilyl)benzene, 2-(trimethoxysilylethyl)pyridine, bis(triethoxysilylpropyl)amine, para-trifluoromethylterafluorophenyltrimethoxysilane, (tridecafluoro-1,1,2,2-tetrahydro-octyl)trimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 3-sulfoxypropyltrimethoxysilane, isocyanatopropyltrimethoxysilane 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and trimethoxypropylbenzylcarbamate.
12. The sol-gel composition of claim 1 , wherein the bis(trialkoxysilylalkyl)benzene is BTEB.
13. The sol-gel composition of claim 1 , wherein the sol-gel composition is swellable to at least five times its dry volume, when placed in excess acetone.
14. The sol-gel composition of claim 1 , wherein the sol-gel composition absorbs from about 5 to about 15 times its dry weight, of acetone, when placed in excess acetone.
15. The sol-gel composition of claim 14 , wherein the sol-gel composition absorbs from about 8 to about 12 its dry weight, of acetone, when placed in excess acetone.
16. The sol-gel composition of claim 1 , wherein the sol-gel composition has a pore volume of from about 0.9 mL/g to about 1.1 mL/g.
17. The sol-gel composition of claim 1 , wherein the sol-gel composition has a surface area from about 600 m 2 /g to about 1200 m 2 /g.