Jung Se-Hyeong, Meyer Fabian, Hörnig Sven, Bund Michelle, Häßel Bernhard, Guerzoni Luis Paulo Busca, De Laporte Laura, Ben Messaoud Ghazi, Centeno Silvia P, Pich Andrij
Functional and Interactive Polymers, Institute of Technical and Macromolecular Chemistry, Worringerweg 2, 52074, Aachen, Germany.
DWI-Leibniz Institute for Interactive Materials e.V., Forckenbeckstr. 50, 52074, Aachen, Germany.
Small. 2024 Jan;20(2):e2303444. doi: 10.1002/smll.202303444. Epub 2023 Sep 13.
In this report, a versatile method is demonstrated to create colloidal suprastructures by assembly and supramolecular interlinking of microgels using droplet-based microfluidics. The behavior of the microgels is systematically investigated to evaluate the influence of their concentration on their distribution between the continuous, the droplet phase, and the interface. At low concentrations, microgels are mainly localized at the water-oil interface whereas an excess of microgels results, following the complete coverage of the water-oil interface, in their distribution in the continuous phase. To stabilize the colloidal suprastructure, on-chip gelation is introduced by adding natural polyphenol tannic acid (TA) in the water phase. TA forms interparticle linking between the poly(N-vinylcaprolactam) (PVCL) microgels by supramolecular interactions. The combination of supramolecular interlinking with the variation of the microgel concentration in microfluidic droplets enables on-chip fabrication of defined colloidal suprastructures with morphologies ranging from colloidosomes to colloidal supraballs. The obtained supracolloidal structures exhibit a pH-responsive behavior with a disintegration at alkaline conditions within a scale of seconds. The destabilization process results from the deprotonation of phenolic groups and destruction of hydrogen bonds with PVCL chains at higher pH.
在本报告中，展示了一种通用方法，通过基于液滴的微流控技术，利用微凝胶的组装和超分子交联来创建胶体超结构。系统研究了微凝胶的行为，以评估其浓度对其在连续相、液滴相和界面之间分布的影响。在低浓度下，微凝胶主要定位在水油界面，而微凝胶过量时，在水油界面被完全覆盖后，它们会分布在连续相中。为了稳定胶体超结构，通过在水相中添加天然多酚单宁酸（TA）引入片上凝胶化。TA通过超分子相互作用在聚（N-乙烯基己内酰胺）（PVCL）微凝胶之间形成颗粒间连接。超分子交联与微流控液滴中微凝胶浓度变化的结合，使得能够在片上制造出形态从胶体囊泡到胶体超球不等的确定胶体超结构。所获得的超胶体结构表现出pH响应行为，在碱性条件下几秒钟内就会解体。去稳定化过程是由于酚基团的去质子化以及在较高pH下与PVCL链的氢键破坏所致。
