Colloids and Surfaces A: Physicochem. Eng. Aspects 441 (2014) 549–555 Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects jo ur nal ho me page: www.elsevier.com/locate/colsurfa Water intrusion/extrusion in hydrophobized mesoporous silica gel in a wide temperature range: Capillarity, bubble nucleation and line tension effects Ya. Grosu a , O. Ievtushenko a,b,c , V. Eroshenko a,∗ , J.M. Nedelec b,c , J.P.E. Grolier b,c,∗ a National Technical University of Ukraine, Kyiv Polytechnic Institute, Laboratory of Thermomolecular Energetics, Prospect Peremogy 37, 03056 Kyiv, Ukraine b Clermont Université, ENSCCF, Institute of Chemistry of Clermont-Ferrand, BP 10448, 63000 Clermont-Ferrand, France c CNRS, UMR 6296, ICCF, 24 Av. des Landais, 63171 Aubière, France h i g h l i g h t s • Intrusion and extrusion pressures of {silica gel C8 + water} system were investigated in the 10–150 ◦ C tem- perature range. • Unexpected non-linear temperature dependence for extrusion pressure is observed. • Results are treated by means of cap- illary and nucleation theories. • Temperature dependence of contact angles is calculated under the “Sharp- kink” approximation. • Line tension effect is taken into account. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 20 August 2013 Received in revised form 2 October 2013 Accepted 3 October 2013 Available online xxx Keywords: Interface Porous media PV-isotherm Heterogeneous lyophobic system Contact angle a b s t r a c t The pressure under which forced intrusion of non-wetting liquid into capillary takes place (intrusion pressure) is a very important parameter for a number of devices using intrusion/extrusion characteris- tics of porous materials. For molecular springs, dumpers and shock-absorbers based on heterogeneous lyophobic systems (HLS) their efficiency is determined by the pressure of both intrusion and extrusion, the latter being the pressure under which intruded liquid extrudes from the capillary. In this paper the temperature dependence of intrusion and extrusion pressures of a {grafted silica gel + water} HLS is investigated in the 10–150 ◦ C temperature range. An unexpected non-linear temperature dependence of extrusion pressure is obtained. The interpretation of these results is provided with the help of capil- lary and bubble nucleation theories. The calculations include the line tension effect and contact angles temperature dependence. © 2013 Elsevier B.V. All rights reserved. ∗ Corresponding author at: Clermont Université, ENSCCF, Institute of Chemistry of Clermont-Ferrand, BP 10448, 63000 Clermont-Ferrand, France. E-mail addresses: eroshenko@kpi.ua, vae29@i.com.ua (V. Eroshenko), j-pierre.grolier@univ-bpclermont.fr (J.P.E. Grolier). 1. Introduction Methods of forced intrusion of non-wetting liquid (such as mercury or water porosimetry) are widely used for porous mate- rials characterization in such fields as catalysis, chromatography, adsorption, pharmaceutical and petroleum science [1,2] and are still under improvement [3]. The process of reversible intrusion of water into hydrophobic porous media (with contact angle  ≫ 90 ◦ ) 0927-7757/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.colsurfa.2013.10.022