Esmaeili Amir R, Mir Noshin, Mohammadi Reza
Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
J Colloid Interface Sci. 2020 Aug 1;573:317-327. doi: 10.1016/j.jcis.2020.04.027. Epub 2020 Apr 7.
Alkyl ketene dimer (AKD) is frequently used in paper industry as an inexpensive sizing agent. The formation of a porous structure after curing the solidified AKD for an extra-long time (4-6 days) results in superhydrophobicity. In this study, a facile and low-cost method was utilized to turn the surface of AKD superhydrophobic in a very short period of time.
We fabricated superhydrophobic coatings by dipping glass and paper substrates in molten AKD and then treating them with ethanol after solidification. The samples were characterized by X-ray diffraction, Scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, Confocal laser scanning microscopy, and dynamic contact angle goniometry.
The results show that briefly treating the coatings, obtained from isothermally heated AKD melt at 40 °C for 3 min, with ethanol leads to superhydrophobicity with advancing and receding contact angles of 158.7 ± 1.4° and 156.8 ± 0.9°, respectively. By increasing the melt temperature to 70 °C and its heating time to 6 h followed by ethanol treatment, the advancing and receding contact angles increased to 163.7 ± 1.3° and 162.6 ± 1.2°, respectively. This enhancement in superhydrophobicity is due to the formation of porous, entangled irregular micro/nano textures that create air cushions on the surface resulting in droplet state transition from Wenzel to Cassie.
烷基烯酮二聚体（AKD）作为一种廉价的施胶剂常用于造纸工业。将固化的AKD额外长时间（4 - 6天）固化后形成的多孔结构会导致超疏水性。在本研究中，采用了一种简便且低成本的方法在极短时间内使AKD表面具有超疏水性。
我们通过将玻璃和纸张基材浸入熔融的AKD中，然后在固化后用乙醇处理来制备超疏水涂层。通过X射线衍射、扫描电子显微镜、傅里叶变换红外光谱、X射线光电子能谱、共聚焦激光扫描显微镜和动态接触角测量仪对样品进行表征。
结果表明，将在40℃等温加热3分钟的AKD熔体得到的涂层用乙醇进行短暂处理后，前进接触角和后退接触角分别为158.7±1.4°和156.8±0.9°，从而产生超疏水性。将熔体温度提高到70℃并将加热时间延长至6小时，随后进行乙醇处理，前进接触角和后退接触角分别增加到163.7±1.3°和162.6±1.2°。这种超疏水性的增强是由于形成了多孔、缠结的不规则微/纳米纹理，这些纹理在表面上形成气垫，导致液滴状态从Wenzel转变为Cassie。
