Abstract：
Molecular transport processes in printed polymer droplets hold enormous importance for understanding wetting phenomena and designing systems in applications such as encoding, electronics, photonics, and sensing. This paper studies thickness-dependent dewetting modes that are activated by thermal annealing and driven by interfacial interactions within microscopically confined polymeric features. The printing of poly(2-vinylpyridine) is performed in a regime where coffee-ring effects lead to strong thinning of the central region of the deposit. Thermal annealing leads to two different modes of dewetting that depend on the thickness of the central region. Mode I refers to the formation of randomly positioned small features surrounded by large hemispherical ones located along the periphery of the printed features and occurs when the central regions are thin. Observed at large central thicknesses, Mode II mediates significant molecular transport from edges toward the center of the printed droplet with thermal annealing and forms a hemispherical feature from the initial ring-like deposit. The selective adsorption of red, green, and blue emitting quantum dots over the poly(2-vinylpyridine) results in photoluminescent patterns. The selective assembly of photoluminescent quantum dots over patterned surfaces leads to deterministic and stochastic features beneficial to creating security labels for anti-counterfeiting applications.
摘要：
印刷聚合物液滴中的分子传输过程对于理解润湿现象和设计编码等应用中的系统至关重要。电子,光子学,和感应。本文研究了厚度相关的去湿模式，这些模式是通过热退火激活的，并由微观约束的聚合物特征内的界面相互作用驱动。聚（2-乙烯基吡啶）的印刷是在咖啡环效应导致沉积物中心区域强烈变薄的情况下进行的。热退火导致取决于中心区域的厚度的两种不同的去湿模式。模式I是指由沿着印刷特征的周边定位的大的半球形特征包围的随机定位的小特征的形成,并且当中心区域薄时发生。在大中心厚度处观察到，模式II通过热退火介导从边缘向打印液滴中心的大量分子传输，并从初始环状沉积物形成半球形特征。对红色的选择性吸附，绿色,和在聚(2-乙烯基吡啶)上的发蓝光的量子点产生光致发光图案。光致发光量子点在图案化表面上的选择性组装导致有利于产生用于防伪应用的安全标签的确定性和随机性特征。
