基于界面相互干扰能分析法的二乙醇胺水溶液自发浸润聚偏氟乙烯疏水微孔膜的机理研究

Mechanism of the spontaneous invasion of aqueous diethanolamine solutions into polyvinylidene hydrophobic microporous membranes based on the analysis of interfacial interaction energy

通过van Oss范德华表面张力拟合法,拟合出了聚偏氟乙烯(PVDF)疏水微孔膜和润湿PVDF膜的各界面张力,证实了表面活性剂的吸附入侵机理同样适用于二乙醇胺(DEA)溶液浸润PVDF膜。通过吸附实验和Hyper Chem软件的分子优化推算出了DEA分子在固液界面的相互干扰能,利用Hamaker算法计算了DEA分子与PVDF膜的相互干扰能。结合DEA分子的固液、固气相互干扰能和Starov界面吸附常数方程,定量计算出了DEA分子在PVDF膜上的固气界面吸附常数几乎为0,即DEA分子在自发浸润过程中吸附在固气表面的可能性极小,从而证实了DEA溶液缓慢浸润PVDF疏水微孔膜的机理是由于固液界面吸附导致固液界面张力下降而引起的液气界面附加压力反向。从相互干扰能的角度研究了润湿现象,并基于所得机理提出了抵抗润湿的方法。

The van der Waals surface tension fitting method according to van Oss has been used to fit the interfacial tension of unwetted and wetted polyvinylidene （PVDF） membranes. It was confirmed that the adsorption-invasion mechanism of surfactants is also suitable for treatment of the process of wetting PVDF membranes with diethanolamin （DEA） solutions. The interaction energy of DEA molecules on the solid-liquid（S-L） interface was calculated using the results of adsorption experiments and molecular optimization with HyperChem. The interaction energy of the solid-gas （S-V） interface was calculated using the Hamaker constant algorithm. Based on the equation of Starov, the adsorption constant of DEA molecules on the S-V interface of the PVDF membrane was calculated to be almost zero, showing that the reason why the DEA solution just slowly wetted the PVDF hydrophobic microporous membrane was the additional pressure reversal, caused by the decrease on the S-L interface tension due to the adsorption of S-L interface. The wetting phenomenon was studied by the method of interfacial interaction energy, and an effective approach to prevent wetting has been proposed.