Kim Jihye, Hwang Hyesun, Butt Hans-Jürgen, Wooh Sanghyuk
School of Chemical Engineering & Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea.
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
J Colloid Interface Sci. 2021 Apr 15;588:157-163. doi: 10.1016/j.jcis.2020.12.072. Epub 2020 Dec 31.
Surface-templated evaporation-driven supraparticle synthesis is a versatile method for supraparticle fabrication. A supraparticle is formed by drying droplet of a colloidal dispersion on liquid repellent surfaces, allowing precise control of the size and mean composition of the supraparticles. The crucial factor determining the morphology is the motion of the contact line of the dispersion droplet on the liquid repellent surface. Here, we study effects of (i) the apparent contact angle and (ii) the contact line friction of a droplet on the shape of the supraparticle. In order to change the initial apparent contact angle of the dispersion droplet a surfactant was added to decrease surface tension. In addition, two different liquid repellent surfaces were used: a polydimethysiloxane (PDMS) grafted surface and a lubricated surface. Both surfaces exhibited distinctly different contact line friction during evaporation. As the initial contact angle of a droplet decreases and friction of a contact line increases, flatter supraparticles are fabricated. By using this simple manipulation principle, eventually, various shapes of supraparticles can be obtained, such as mushroom, hemispherical, convex lens, and disk shapes. This study presents fundamental and critical information that allow us to manipulate the shape of a supraparticle via surface-templated evaporation-driven synthesis that increases the scalability of supraparticles for use in a wide range of applications.
表面模板化蒸发驱动超粒子合成是一种用于制造超粒子的通用方法。超粒子是通过在疏液表面上干燥胶体分散液滴形成的，从而可以精确控制超粒子的尺寸和平均组成。决定形态的关键因素是分散液滴在疏液表面上的接触线运动。在此，我们研究了（i）表观接触角和（ii）液滴的接触线摩擦力对超粒子形状的影响。为了改变分散液滴的初始表观接触角，添加了一种表面活性剂以降低表面张力。此外，使用了两种不同的疏液表面：聚二甲基硅氧烷（PDMS）接枝表面和润滑表面。在蒸发过程中，这两种表面均表现出明显不同的接触线摩擦力。随着液滴的初始接触角减小且接触线的摩擦力增加，会制造出更扁平的超粒子。通过使用这种简单的操纵原理，最终可以获得各种形状的超粒子，例如蘑菇形、半球形、凸透镜形和盘形。这项研究提供了重要的基础信息，使我们能够通过表面模板化蒸发驱动合成来操纵超粒子的形状，从而提高超粒子在广泛应用中的可扩展性。
