Dissipative Forced Intrusion Of Water In Hydrophobic Porous Silica: A New Field of Applications For MCM-41 Type Material
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Dissipative Forced Intrusion Of Water In Hydrophobic Porous Silica: A New Field of Applications For MCM-41 Type Materials Benoit Lefevre1, Pierre F. Gobin1, Thierry Martin2, Anne Galarneau2 and Daniel Brunel2 Laboratoire GEMPPM, UMR 5510, Insa de Lyon, 20, Avenue Albert Einstein, F-69621 Villeurbanne, France 2 Laboratoire de Matériaux Catalytiques et Catalyse en Chimie Organique, UMR 5618, 8, rue de l’Ecole Normale, F-34296 Montpellier Cedex 05, France 1
ABSTRACT Recently microporous and mesoporous materials were found to be particularly suitable for a new type of applications in the mechanical field. This paper reports experimental features about the dissipative forced intrusion of water in highly hydrophobic mesoporous materials: this phenomenon can be used to develop a new type of dampers and/or actuators. Silica-based materials behavior was investigated. Among them, MCM-41 exhibit original and interesting properties towards the potential developments of dampers and appear to be of great interest for the comprehension of energy dissipation mechanisms. INTRODUCTION
In the last decades, variety of microporous and mesoporous materials was developed for applications in catalysis, chromatography and adsorption. Great attention has been paid to the control of (i) pore surface chemistry and (ii) textural properties such as pore size distribution, pore size and shape. Recently, a new field of applications for these materials has been highlighted [1][2][3]: by forcing a non-wetting liquid to invade a porous solid by means of an external pressure, mechanical energy can be converted to interfacial energy. The capillary pressure, Pint , required for liquid intrusion in a cylindrical pore can be written from the LaplaceWashburn relation 1, Pint = −
2γ cosθ a r
(1)
γ being the liquid surface tension, r the pore radius and θa the advancing contact angle between the liquid and the solid surface. This stored energy can then be completely or partially restored once the system recovers the initial state after liquid extrusion. Depending on the texture and surface properties of the matrix, the considered system could be applied for either energy storage (springs, actuators) or dissipation (damping). Actually, the possibility to dissipate mechanical energy depends on the presence of pressure hysteresis ∆P in the intrusion-extrusion process (∆P=Pint – Pext , Pext being the extrusion pressure). The physical principle is in fact close to porosimetry experiments based on mercury injection, but because of evident environmental disadvantages of mercury manipulation, it Q11.9.1 Downloaded from https:/www.cambridge.org/core. University of Arizona, on 12 Apr 2017 at 09:52:30, subject to the Cambridge Core terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-726-Q11.9
appeared convenient to find other (solid-liquid) systems. Hydrophobic solids and water were successfully tested as alternative systems [4]. The first results were obtained using modified mesoporous silica gels [4][5][6][7][8]. For su
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