Non-textured laser modification of silica glass surface: Wettability control and flow channel formation
Non-textured laser modification of silica glass surface: Wettability control and flow channel formation
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DOI：
10.1016/j.apsusc.2016.03.040
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发表时间：
2016-05
影响因子：
6.7
通讯作者：
Yuko Aono;A. Hirata;H. Tokura
中科院分区：
文献类型：
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作者：
Yuko Aono;A. Hirata;H. Tokura
通过红外激光照射对石英玻璃表面的局部润湿性进行改性。石英玻璃表面在单键CF3或单键(CH3)2末端官能团的存在下表现出疏水性，这些官能团通过热处理分解，分解程度取决于所施加的热量。激光照射可根据照射条件控制剩余官能团的数量；去离子水在激光改性表面上的接触角范围为100°至40°。 XPS 分析证实润湿性的变化与剩余单键 CF3 基团的数量相对应。通过SEM和AFM观察，激光照射实现了表面改性，且不会对表面造成任何裂纹或损伤；此外，表面对可见光的透明度和表面粗糙度不受影响。该方法适用于平面流道系统。滴下的水仅在经激光照射修改的亲水且不可见的线上扩散，而不会形成任何凹槽。这表明修改后的线可以充当表面通道。此外，在润湿性沿其长度逐渐变化的通道上也证明了液体的自输送。疏水侧的水滴由于接触角滞后力而自行输送到亲水侧，无需任何致动器或外力。
Local wettability of silica glass surface is modified by infrared laser irradiation. The silica glass surface exhibits hydrophobic property in the presence of single bondCF3or single bond(CH3)2terminal functional groups, which are decomposed by thermal treatment, and degree of the decomposition depends on the applied heat. Laser irradiation can control the number of remaining functional groups according to the irradiation conditions; the contact angle of deionized water on the laser modified surfaces range from 100° to 40°. XPS analysis confirms that the variation in wettability corresponds to the number of remaining single bondCF3groups. The laser irradiation achieves surface modification without causing any cracks or damages to the surface, as observed by SEM and AFM; moreover, surface transparency to visible light and surface roughness remains unaffected. The proposed method is applied to plane flow channel systems. Dropped water spreads only on the hydrophilic and invisible line modified by the laser irradiation without formation of any grooves. This indicates that the modified line can act as a surface channel. Furthermore, self-transportation of liquid is also demonstrated on a channel with gradually-varied wettability along its length. A water droplet on a hydrophobic side is self-transported to a hydrophilic side due to contact-angle hysteresis force without any actuators or external forces.