Wavelength-Sensitive Optical Tweezers Using Black-Si Nanospikes for Controlling the Internal Polarity of a Polymer Droplet
Wavelength-Sensitive Optical Tweezers Using Black-Si Nanospikes for Controlling the Internal Polarity of a Polymer Droplet
复制标题
DOI：
10.1021/acsanm.2c04222
复制
发表时间：
2022-12-22
影响因子：
5.9
通讯作者：
Tsuboi, Yasuyuki
中科院分区：
文献类型：
--
作者：
Nagai, Tatsuya;Yuyama, Ken-ichi;Tsuboi, Yasuyuki
最近，我们开发了一种基于纳米结构硅(黑硅)的光镊子技术。钉状的纳米结构增强了入射光的电场，从而加强了镊子的抓地力。在本研究中，我们将镊子应用于水溶液中的聚(N-异丙基丙烯酰胺)(PNIPAM)。这种聚合物在光学操纵化学领域中经常被用作靶标。利用该技术，我们成功地在黑硅表面形成了PNIPAM微滴。PNIPAM液滴的形成在聚合物化学、分析化学和液滴化学中具有重要意义。重要的是，在这里，我们证明了捕获行为对捕获激光的波长(1064或808 nm)非常敏感。使用808 nm激光可以捕获聚合物，效率是使用1064 nm激光的100倍。此外，在808 nm激光照射下，液滴的化学结构可以被调制。通过改变808 nm处的激光强度，成功地改变了液滴的内极性，而在1064 nm处，液滴的内极性是固定的。PNIPAM微滴的产生纯粹是由于808 nm激光的光学力增强。激光波长的选择在黑硅基光钳中非常重要。
Recently, we have developed an optical tweezers technique based on nanostructured Si (Black-Si). The spike-like nanostructure enhances the electric field of the incident light, thereby strengthening the grip made by the tweezers. In the present study, we applied the tweezers to poly(N-isopropylacrylamide) (PNIPAM) in aqueous solutions. This polymer has frequently been used as a target in the field of optical manipulation chemistry. Using the technique, we succeeded in forming a PNIPAM microdroplet on the surface of the Black-Si. The formation of PNIPAM droplets is important in polymer chemistry, analytical chemistry, and droplet chemistry. Importantly, herein, we demonstrate that the trapping behavior is very sensitive to the wavelength of the trapping laser light (1064 or 808 nm). Using 808 nm laser light, the polymer can be trapped with a 100-fold-greater efficiency compared to that using 1064 nm laser light. Moreover, with 808 nm laser light, the chemical structure of the droplet can be modulated. By changing the laser intensity at 808 nm, we succeeded in varying the internal polarity of the droplet, while at 1064 nm the polarity is fixed. The production of the PNIPAM microdroplet is purely due to the enhanced optical force of the 808 nm laser light. The selection of laser wavelength is very important in the Black-Si-based optical tweezers.