Kim Gi-Hong, Kang Dong-Ho, Jung Bich-Nam, Shim Jin-Kie
Korea Packaging Center, Korea Institute of Industrial Technology, Bucheon 14449, Korea.
Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Korea.
Polymers (Basel). 2022 Feb 21;14(4):833. doi: 10.3390/polym14040833.
Cellulose nanofibrils (CNFs) have attracted much attention because of their renewability and potential biocompatibility. However, CNFs are extremely hydrophilic due to the presence of a large number of hydroxyl groups, limiting their use as a water-resistant material. In this work, we controlled the adsorption behavior of silica nanoparticles on the surface of CNFs by adjusting the synthesis conditions. The silica nanoparticle size and packing efficiency on the CNF surface could be controlled by varying the ammonium hydroxide and water concentrations. In addition, hexadecyltrimethoxysilane (HDTMS) was successfully grafted onto CNF or CNF/silica nanocomposite surfaces, and the quantitative content of organic/inorganic substances in HDTMS was analyzed through XPS and TGA. The HDTMS-modified CNF/silica nanocomposites were more advantageous in terms of hydrophobicity than the HDTMS-modified CNF composites. This is because the silica nanoparticles were adsorbed on the surface of the CNFs, increasing the surface roughness and simultaneously increasing the amount of HDTMS. As a result, the HDTMS-modified CNFs showed a water contact angle (WCA) of ~80°, whereas HDTMS-modified CNF/silica nanocomposites obtained superhydrophobicity, with a WCA of up to ~159°. This study can provide a reference for the expansion of recyclable eco-friendly coating materials via the adsorption of silica nanoparticles and hydrophobic modification of CNF materials.
纤维素纳米纤维（CNFs）因其可再生性和潜在的生物相容性而备受关注。然而，由于存在大量羟基，CNFs具有极强的亲水性，这限制了它们作为防水材料的应用。在这项工作中，我们通过调整合成条件来控制二氧化硅纳米颗粒在CNFs表面的吸附行为。通过改变氢氧化铵和水的浓度，可以控制CNFs表面二氧化硅纳米颗粒的尺寸和堆积效率。此外，十六烷基三甲氧基硅烷（HDTMS）成功接枝到CNF或CNF/二氧化硅纳米复合材料表面，并通过XPS和TGA分析了HDTMS中有机/无机物的定量含量。HDTMS改性的CNF/二氧化硅纳米复合材料在疏水性方面比HDTMS改性的CNF复合材料更具优势。这是因为二氧化硅纳米颗粒吸附在CNFs表面，增加了表面粗糙度，同时增加了HDTMS的含量。结果，HDTMS改性的CNFs的水接触角（WCA）约为80°，而HDTMS改性的CNF/二氧化硅纳米复合材料获得了超疏水性，WCA高达约159°。这项研究可为通过吸附二氧化硅纳米颗粒和对CNF材料进行疏水改性来扩展可回收环保涂料材料提供参考。
