Division of Applied Chemistry , Graduate School of Engineering, Osaka Institute of Technology , 5-16-1, Omiya, Asahi-ku , Osaka 535-8585 , Japan.
Department of Ecology and Systematics , Graduate School of Agriculture, Hokkaido University , Kita 9, Nishi 9, Kita-ku , Sapporo 060-8589 , Japan.
Langmuir. 2019 May 7;35(18):6169-6178. doi: 10.1021/acs.langmuir.9b00771. Epub 2019 Apr 24.
Some aphids that live in the leaf galls of the host plant are known to fabricate liquid marbles consisting of honeydew and wax particles as an inner liquid and a stabilizer, respectively. In this study, the liquid marbles fabricated by the galling aphids, Eriosoma moriokense, were extensively characterized with respect to size and size distribution, shape, nanomorphology, liquid/solid weight ratio, and chemical compositions. The stereo microscopy studies confirmed that the liquid marbles have a near-spherical morphology and that the number-average diameter was 368 ± 152 μm, which is 1 order of magnitude smaller than the capillary length of the honeydew. The field emission scanning electron microscopy studies indicated that micrometer-sized wax particles with fiber- and dumpling-like shapes coated the honeydew droplets, which rendered the liquid marbles hydrophobic and nonwetting. Furthermore, the highly magnified scanning electron microscopy images confirmed that the wax particles were formed with assemblage of submicrometer-sized daughter fibers. The contact angle measurements indicated that the wax was intrinsically hydrophobic and that the liquid marbles were stabilized by the wax particles in the Cassie-Baxter model. The weight ratio of the honeydew and the wax particles was determined to be 96/4, and the honeydew consisted of 19 wt % nonvolatile components and 81 wt % water. The H nuclear magnetic resonance, Fourier transform infrared spectroscopy, and mass spectroscopy studies confirmed that the wax mainly consisted of triglycerides and that the honeydew mainly consisted of saccharides (glucose and fructose) and ribitol. The atomic force microscopy studies confirmed that honeydew is sticky in nature.
一些生活在宿主植物叶瘿中的蚜虫被发现能够制造出由蜜露和蜡颗粒分别作为内部液体和稳定剂组成的液滴。在这项研究中，对由瘿蚜 Eriosoma moriokense 制造的液滴进行了广泛的特性分析，包括大小和尺寸分布、形状、纳米形态、液/固重量比以及化学成分。立体显微镜研究证实，液滴具有近球形的形态，数均直径为 368 ± 152 μm，比蜜露的毛细长度小 1 个数量级。场发射扫描电子显微镜研究表明，微米级的蜡颗粒呈纤维状和饺子状，覆盖在蜜露液滴上，使液滴具有疏水性和不浸润性。此外，高倍扫描电子显微镜图像证实蜡颗粒是由亚微米级的子纤维组装而成的。接触角测量表明蜡本质上是疏水性的，液滴是通过蜡颗粒在 Cassie-Baxter 模型中稳定的。蜜露和蜡颗粒的重量比被确定为 96/4，蜜露由 19 wt %的非挥发性成分和 81 wt %的水组成。氢核磁共振、傅里叶变换红外光谱和质谱研究证实，蜡主要由甘油三酯组成，而蜜露主要由糖（葡萄糖和果糖）和核糖醇组成。原子力显微镜研究证实蜜露具有粘性。
