Understanding the Origin of Swelling Force in Organically Modified Silica

Evan Hagedorn


Swellable organically modified silica swells in the presence of organic liquids, producing forces in excess of 500 N/g. The mechanism of force generation is hypothesized to be due to the spring-like behavior of the change in the interparticle Si-O-Si bond angle. IR spectra of swellable organosilica were collected as a function of applied force. The Si-O-Si vibrational band was analyzed and found to decrease with applied force. Spectra deconvolution was used to determine the peak position and the area of the Si-O-Si vibrational band so that the average Si-O-Si angle could be calculated. Forces of around 109 N/g were calculated for swellable organosilica by Gaussian modeling. If true, the measured force is around 106 N/g less than the maximum potential force that could be generated. The research provides a novel interdisciplinary analysis of how force can be generated from bond deflection.