(605e) Synthesis and Characterization of Organic-Functionalized Pure-Silica-Zeolite

Authors: 
Lew, C. M., University of California, Riverside
Davis, M. E., California Institute of Technology
Li, Z., University of California, Riverside
Li, S., University of California, Riverside
Medina, D. I., University of California, Riverside
Yan, Y., University of Delaware
Hwang, S., California Institute of Technology
Sun, W., University of California, Riverside


As the feature size of next-generation microprocessors
decreases, the need for low-dielectric constant (low-k) materials with high
mechanical strength is an increasing concern.  Many potential porous materials
take advantage of the low k value of air, which is about 1, but they are often
amorphous in nature and thus lack mechanical strength.  Porous zeolites,
however, are highly crystalline and have a high elastic modulus while retaining
the low k values of amorphous porous silica materials.[1] 
Since water has a high k value, moisture adsorption is a serious concern for
all porous low-k materials.  Consequently, along with low k and high elastic
modulus values, hydrophobicity is becoming an increasingly important parameter.[2],[3] 
To combat this problem, post-spin-on silylation treatments with
chlorotrimethylsilane and hexamethyldisilazane have been performed, and
pure-silica zeolite (PSZ) MFI has been functionalized with
methyltrimethoxysilane.[4] 
Here, we report an organic functionalized pure-silica zeolite with an MFI-type
structure prepared through a direct-synthesis method by adding a fluorinated
silane to the synthesis solution, and the added fluorine functionality
increased the hydrophobicity of the zeolite.  The zeolite was characterized by x-ray
diffraction, 29Si solid-state nuclear magnetic resonance spectroscopy,
nitrogen adsorption, FT infrared spectroscopy, and thermogravimetric analysis. 
Spin-on films from the nanoparticle suspension exhibited higher water contact
angles than pure-silica zeolite MFI films, and the zeolite powders had low
water content.




[1]
Li, Z.J.; Li, S.; Luo, H.M.; Yan, Y.  Adv. Funct. Mater.  2004, 14,
1019-1024.

[2]
Wang, Z.B.; Mitra, A.P.; Wang, H.T.; Huang, L.M.;Yan, Y.S.  Adv. Mater.  2001,
13, 1463-1466.

[3]
Li, Z.J.; Lew, C.M.; Li, S.; Medina, D.I.; Yan, Y.  J. Phys. Chem. B 2005,
109, 8652-8658.

[4]
Li, S.; Li, Z.J.; Medina, D.; Lew, C.; Yan, Y.  Chem. Mater. 2005,
17, 1851-1854.