Two-dimensional sol-gel transition in silica alkoxides at the air/water interface.
We have investigated the 2D viscoelastic behavior of the reactive sol-gel transition of silica alkoxides deposited at the air/acidic water interface of a Langmuir trough by oscillatory interfacial rheology. The storage and loss moduli increased with time as the hydrolysis-condensation reaction took place. There was evidence of a 2D gel point, which was discussed within the percolation theory framework. The power law dependence value of n=0.63 was similar to those found for bulk systems. The final network had a low fractal dimension value of df=1.17 (for a 2D system) indicating a rather open structure, in agreement with acidic catalysis, and a somewhat low effective modulus of 20 MPa.
Tadjoa
Odile
O
Universite de Lyon 1, Lyon F-69003, France.
Cassagnau
Philippe
P
Chapel
Jean Paul
JP