CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius Street, Orlando, Florida 32826, United States.
J Phys Chem B. 2021 Dec 16;125(49):13533-13541. doi: 10.1021/acs.jpcb.1c07237. Epub 2021 Dec 6.
Accessing the colloidal dynamics non-invasively and continuously during the phase transition of a colloidal system is challenging but critical. Here, we demonstrate the use of spatiotemporal coherence-gated light scattering for studying the internal dynamics of drying colloidal droplets. The continuously acquired signal originates from a picoliter-sized volume located at the droplet-substrate interface. The measurement is non-contact, non-invasive, and label free and permits real-time observations of both optical and mechanical changes in the measurement volume. Additionally, some macroscopic descriptors of the drying process can be constructed from the microscopic measurement, providing ample information of the process. Implemented with an endoscopic-like probe, this system can be easily incorporated into the existing drop profiling instruments, which is potential for the full characterization of dynamic colloidal droplets.
在胶体系统的相变过程中，非侵入式且连续地获取胶粒动力学信息极具挑战，但又非常关键。在此，我们展示了时空相干门控光散射在研究干燥胶粒液滴内部动力学方面的应用。该连续采集的信号源自位于液滴-基底界面的皮升级别体积内。这种测量方法是非接触、非侵入式且无需标记的，可实时观测测量体积中的光学和力学变化。此外，还可以从微观测量中构建一些干燥过程的宏观描述符，为该过程提供充分的信息。通过采用内窥镜式探头，该系统可以很容易地集成到现有的液滴形貌测量仪器中，这对于动态胶体液滴的全面特性表征具有很大的潜力。
