Determination of water intrusion heat in hydrophobic microporous materials by high pressure calorimetry

Thermodynamic and operational properties of heterogeneous lyophobic systems

“…Theoretically predicted and experimentally observed properties of heterogeneous lyophobic systems based on different types of matrices ( const r  or var r  ) (Coiffard et al 2005;Eroshenko 1987bKarbowiak et al 2009Karbowiak et al , 2010, offer the prospect of creating a fundamentally new working mediums for nanotechnology (Eroshenko 1981a(Eroshenko , 1996, cost-saving and ecological friendly systems and equipment in modern energetics (Eroshenko 1996(Eroshenko , 1997(Eroshenko , 2001aHan and Qiao 2007;Iwatsubo et al 2008;Martin et al 2002;Qiao et al 2006 …”

“…Particularly, due to the molecular bonds number decrease (molecules were "wrested" from the bulk liquid phase and placed in a microcapillary), the liquid surface tension in such capillary is lower than in the bulk phase (Rusanov 1981, Kirkwood andBuff 1949), which is confirmed by molecular dynamic simulations according to which a single-or double-chain of liquid molecules is formed (Mann and Halls 2003;Moravsky and Loutfy 2004). Whereas, in water intrusion experiments on superhydrophobic silicalites (Coiffard et al 2005;Eroshenko 2000Eroshenko , 2001bKarbowiak et al 2009Karbowiak et al , 2010 with the pore radius ~0, 25 r nm measured Laplace capillary pressure was about 5-7 times lower than calculated on the basis that confined and bulk water surface tensions are equal (Eroshenko 2002). Correction factor B may be useful for more accurate calculation of non-standard processes in heterogeneous nanosystems, like HLS thermal effects of compression (intrusion) and decompression (extrusion).…”

“…Here and below the cosθ module is used and the value of contact angle θ is assumed to be taken for the planer "liquid -solid" interface. Correcting factor B is used in equation (2) to preserve its original phenomenological structure despite the fact that microscopic properties of the liquid confined in the capillary, with diameter comparable with the size of the molecules of the liquid (Coiffard et al 2005;Eroshenko 2000Eroshenko , 2001bKarbowiak et al 2009Karbowiak et al , 2010, may not coincide with its macroscopic properties, which are usually given for a massive phase in the references (Vargaftik 1972). Particularly, due to the molecular bonds number decrease (molecules were "wrested" from the bulk liquid phase and placed in a microcapillary), the liquid surface tension in such capillary is lower than in the bulk phase (Rusanov 1981, Kirkwood andBuff 1949), which is confirmed by molecular dynamic simulations according to which a single-or double-chain of liquid molecules is formed (Mann and Halls 2003;Moravsky and Loutfy 2004).…”

“…Verification of proposed model adequacy was performed using calorimetric and volumetric data (experiment procedure described in (Coiffard et al 2005;Karbowiak et al 2009Karbowiak et al , 2010). Experiments were obtained on three heterogeneous lyophobic systems based on superhydrophobic silicalites with quasi-cylindrical pores (average radius 0~0 , 25nm r ).…”

“…In view of MFI matrices superhydrophobicity (Coiffard et al 2005;Karbowiak et al 2009Karbowiak et al , 2010 (4), (7) and (8), heat flow per pressure variation P Ф can be expressed as:…”