Energetics: A new field of applications for hydrophobic zeolites
Energetics: A new field of applications for hydrophobic zeolites
复制标题
DOI：
10.1021/ja011011a
复制
发表时间：
2001-08-22
影响因子：
15
通讯作者：
Patarin, J
中科院分区：
文献类型：
--
作者：
Eroshenko, V;Regis, RC;Patarin, J
由液体和疏水多孔基质（即多孔固体和非润湿液体）组成的热力学系统具有能量积累、转化、恢复或耗散的特性。1-3将这些系统置于不断增大的静水压力下，当压力P等于毛细管压力PL 1时，观察到液体侵入固体孔隙，毛细管压力PL 1可以用Laplace-Washburn关系表示，其中σ为表面张力，r为孔隙半径，θ为液固接触角（θ）。90)。在非润湿液体侵入多孔材料的过程中，产生了一个携带表面自由能的大界面Ω。该表面（ΔΩ>）的发展导致吉布斯能量（ΔG>）的增加，其可以写成：为了使该能量（ΔG< 0）最小化，系统自发地发展并通过将液体挤出固体的空腔来减小其界面（ΔΩ< 0）。根据外部压力的不同，液体分子可以穿透或从空腔中排出。因此，存在着机械能向界面能的互反转换。当应力受到抑制时，被压缩的非均相系统由于液体的挤压而自发膨胀，从而构成真正的分子弹簧。这一特性可用于工程设备，其中短距离分子力发生诱导重要的努力和大位移3-5，如卫星的太阳能电池板的扩散。目前热力学研究的独创性在于对非均相系统组分的选择。水很适合作为流动相；它是一种极性液体，无污染，易于作为纯相获得，不昂贵，并且具有高表面张力的特点。非常小的水分子，相当于直径为2.8 Å的小球体，能够进入非常小的微孔。水的选择使固相成为疏水性多孔材料。结晶
The thermodynamic systems consisting of a liquid and a lyophobic porous matrix, that is a porous solid and a non wetting liquid, have the property to accumulate, transform, restore or dissipate energy. 1-3 By submitting these systems to an increasing hydrostatic pressure, the intrusion of the liquid into the pores of the solid is observed when the pressure P becomes equal to the capillary pressure PL 1 which can be expressed by the Laplace-Washburn relation where σ is the surface tension, r the radius of the pores, and θ the contact angle between the liquid and the solid (θ. 90). During the intrusion of a nonwetting liquid into a porous material, a large interface Ω carrying the surface free energy is created. The development of this surface (ΔΩ> 0), leads to an increase in the Gibbs energy (ΔG> 0) which may be written asTo minimize this energy (ΔG< 0), the system spontaneously evolves and decreases its interface (ΔΩ< 0) by extrusion of the liquid out of the cavities of the solid. Depending on the external pressure, the molecules of the liquid can penetrate or are expelled from the cavities. 2, 4 Therefore, there is a reciprocal transformation of mechanical energy into interfacial energy. When the stress is suppressed, the compressed heterogeneous system spontaneously expands as a result of the extrusion of the liquid and then constitutes a real molecular spring. This property could be used in engineering for devices where short-range molecular forces occur to induce important efforts and large displacements3-5 such as the spreading of solar panels of satellites. The originality of the present thermodynamic study results in the choice of the constituents of the heterogeneous systems. Water is well suited as the mobile phase; it is a polar liquid, not polluting, easy to obtain as a pure phase, not expensive, and characterized by a high surface tension. The very small water molecules, which are comparable to small spheres of 2.8 Å of diameter, are able to access very small micropores. The choice of water imposes the solid phase to be a hydrophobic porous material. Crystallized