Temperature effects on dynamic water absorption into paper.
Mechanisms controlling short time water absorption and the effect of temperature on water absorption into paper were investigated by analyzing previously published data. A dynamic contact angle effect caused by contact line friction explained the liquid uptake dynamics at short times. The water absorption rate increase with temperature is suggested to be controlled by the molecular processes occurring in front of the advancing liquid front. The increase in the non-equilibrium vapor pressure at air-liquid interface leads to higher water molecule adsorption onto fibers and associated lowering of the solid-gas interfacial tension, thereby increasing the wetting velocity and water absorption. The classical Lucas-Washburn equation was found to be inadequate for predicting water absorption into paper both at short times and as a function of temperature.
Laboratory of Paper Coating and Converting and Center for Functional Materials, Abo Akademi University, Porthaninkatu 3, Åbo/Turku FI-20500, Finland. Electronic address: joel.songok@abo.fi.
Joel
J
Songok
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Wushan Road 381, Guanzhou 510640, China.
Pekka
P
Salminen
Laboratory of Paper Coating and Converting and Center for Functional Materials, Abo Akademi University, Porthaninkatu 3, Åbo/Turku FI-20500, Finland.
Martti
M
Toivakka
Contact angle; Liquid penetration; Paper; Temperature dependence