Parallel plications may enhance surface function: physical properties of transparent tunics in colonial ascidians Clavelina cyclus and C. obesa
Parallel plications may enhance surface function: physical properties of transparent tunics in colonial ascidians Clavelina cyclus and C. obesa
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平行褶皱可以增强表面功能：群体海鞘 Clavelina cyclus 和 C. obesa 透明外衣的物理特性
DOI：
10.1017/s0025315419000833
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发表时间：
2019
影响因子：
1.2
通讯作者：
Euichi Hirose
中科院分区：
文献类型：
--
作者：
Daisuke Sakai;Hiroshi Kakiuchida;Kenji Harada;Jun Nishikawa;Euichi Hirose
在各种无脊椎动物的体表发现了一系列纳米级突起，称为乳头阵列，这种结构被认为会降低陆地环境中表面的光反射率和水润湿性。然而，其潜在的功能还没有得到很好的研究在水生环境中。棒菌属是集群海鞘，在其外皮基质（即被膜）上具有乳头阵列。本文研究了C. cyclus和C. obesa，如硬度，润湿性和折射率，以评估该结构的功能重要性。两个种的被膜角质层均被乳头阵列所覆盖，C.环弯曲成褶皱，形成平行褶皱。Clavelina束腰外衣非常柔软，并且具有高的防泡沫性和防油性。被膜和海水之间的折射率偏差为0.07-0.095 589 nm的光（D线）。严格耦合波分析（RCWA）表明，乳头阵列略有减少表面上的反射率和平行褶皱减少的反射率更大。模仿平行褶皱的纳米印迹板比平板具有更高的气泡排斥性和更低的反射率。这些发现支持了皱襞和乳头排列的功能重要性。
An array of nano-scale protrusions, called the nipple array, is found on the body surface of various invertebrates, and this structure is believed to decrease light reflectance and water wettability on the surface in the terrestrial environment. However, its potential functions have not been well studied in aquatic environments. Clavelina spp. are colonial ascidians that have the nipple array on their integumentary matrix (i.e. tunic). We examined the physical properties on the surface of the tunic of C. cyclus and C. obesa, such as hardness, wettability and refractive indices, to evaluate the functional importance of this structure. The tunic cuticle of both species was covered with the nipple array, and the cuticle of C. cyclus was bent into folds forming parallel plications. The Clavelina tunic was very soft and had high bubble- and oil-repellency. The refractive-index deviation between the tunic and seawater was 0.07–0.095 for 589-nm light (D-line). Rigorous coupled wave analysis (RCWA) showed that the nipple array slightly reduced reflectance on the surface and the parallel plications reduced the reflectance still more. The nanoimprinted plates imitating the parallel plications have higher bubble repellency and lower reflectance than the flat plates. These findings support the functional importance of the plications as well as the nipple array.