Zamboni Riccardo, Sebastián-Vicente Carlos, Sadasivan Athira, García-Cabañes Angel, Carrascosa Mercedes, Imbrock Jörg
Institute of Applied Physics, University of Münster, Corrensstraße 2/4, Münster, 48149, Germany.
Departamento de Física de Materiales and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, c/ Francisco Tomás y Valiente 7, 28049, Madrid, Spain.
J Colloid Interface Sci. 2025 Nov 15;698:137976. doi: 10.1016/j.jcis.2025.137976. Epub 2025 May 27.
Photovoltaic charge lithography is an innovative method for printing surface charges from an illuminated iron-doped lithium niobate crystal stamp onto passive dielectric substrates. We hypothesize that this approach can be effectively utilized for droplet manipulation, including electrowetting and droplet transport, offering high reconfigurability similar to optical techniques and avoiding the need for the presence of photosensitive materials in the main platform, simplifying the design of the system and expanding its practical applicability.
We tested photovoltaic charge lithography on a variety of dielectric substrates with different wetting properties. Using incoherent illumination in an air atmosphere, we examined the method's versatility by exploring the effects of varying light exposure on electrowetting and dielectrophoretic droplet attraction. Numerical simulations were also conducted to investigate the interactions between the printed surface charges and the droplets, providing a deeper understanding of the underlying mechanisms.
Our results confirmed the effectiveness of photovoltaic charge lithography for manipulating droplets on diverse dielectric substrates. The method enabled complex functionalities, including light-exposure-tailored electrowetting, droplet transport of single and multiple consecutive droplets (even uphill), and controlled coalescence. Furthermore, the technique proved to be capable of printing surface charges on flexible polymeric substrates, demonstrating its broad applicability. Numerical simulations supported the experimental observations by offering valuable insights into the interactions between the printed charges and the droplets.
光伏电荷光刻是一种创新方法，可将光照掺杂铁的铌酸锂晶体印章上的表面电荷印刻到无源介电基板上。我们假设这种方法可有效用于液滴操控，包括电润湿和液滴传输，具有与光学技术相似的高可重构性，且无需在主平台中存在光敏材料，从而简化系统设计并扩大其实际适用性。
我们在具有不同润湿特性的多种介电基板上测试了光伏电荷光刻。在空气氛围中使用非相干照明，通过探索不同光照对电润湿和介电泳液滴吸引的影响来检验该方法的通用性。还进行了数值模拟以研究印刻的表面电荷与液滴之间的相互作用，从而更深入地了解其潜在机制。
我们的结果证实了光伏电荷光刻在操控不同介电基板上的液滴方面的有效性。该方法实现了复杂功能，包括光照定制的电润湿、单个和多个连续液滴（甚至向上）的液滴传输以及可控聚结。此外，该技术被证明能够在柔性聚合物基板上印刻表面电荷，证明了其广泛的适用性。数值模拟通过对印刻电荷与液滴之间的相互作用提供有价值的见解，支持了实验观察结果。
