Heat release at the wetting front during capillary filling of cellulosic micro-substrates

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:504

Article

Terzis, A.¹  Roumeli, E.^2,3  Weishaupt, K.⁴  Brack, S.¹  Aslannejad, H.⁵  Gross, J.⁶  Helmig, R.⁴  Weigand, B.¹ 

[1] Univ Stuttgart, Inst Aerosp Thermodynam, D-70569 Stuttgart, Germany

[2] CALTECH, Dept Engn & Appl Sci, Pasadena, CA 91125 USA

[3] ETH, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland

[4] Univ Stuttgart, Dept Hydromech & Modelling Hydrosyst, D-70569 Stuttgart, Germany

[5] Univ Utrecht, Dept Earth Sci, NL-3584 CD Utrecht, Netherlands

[6] Univ Stuttgart, Inst Thermodynam & Thermal Proc Engn, D-70569 Stuttgart, Germany

关键词: Paper-based microfluidics;    Thermodynamics;    Capillary dynamics;    Interfacial energy;   

DOI  :  10.1016/j.jcis.2017.06.027

来源: Elsevier

【 摘 要 】

Spontaneous imbibition in cellulosic materials is an expanding field of research due to the direct applicability in paper-based microfluidics. Here, we show experimentally, using simultaneous thermal and optical imaging that the temperature at the wetting front during capillary filling of paper is temporarily increased, even if the imbibed fluid and the cellulosic substrate are initially at isothermal conditions. Several liquids and two types of filter paper, characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, were investigated demonstrating a significant temperature rise at the wetting front that cannot be neglected form the process. The temperature rise is found to be related to the energetics of imbibition compounds, including acid-base contributions, that result in electrostatic attractions as the liquid molecules are adhered on the fiber surfaces upon capillary contact. (C) 2017 Elsevier Inc. All rights reserved.

【 授权许可】

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