Wolter Nadja A, Küttner Hannah, Schmitz Jonas, Karg Matthias, Pich Andrij
Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany.
DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52074, Aachen, Germany.
Small. 2025 Feb;21(7):e2410502. doi: 10.1002/smll.202410502. Epub 2025 Jan 5.
Understanding and controlling the morphology of microgels is crucial for optimizing their properties and functions in diverse areas of application. The fabrication of microgels that exhibit both structural and chemical anisotropy using a template-free approach faces significant challenges. Existing approaches toward such microgels are typically limited to templating methods with low throughput. Here, an alternative bottom-up approach is developed for producing non-spherical N-vinylcaprolactam (VCL) based microgels through semi-batch precipitation polymerization, incorporating a functional comonomer with a liquid crystalline (LC) moiety. 4-methoxybenzoic acid 4-(6-acryloyloxy-hexyloxy)phenyl ester (LCM) is used as the LC comonomer. The resulting morphology of those microgels is tuned to multilobe-, dumbbell-, and raspberry-like shapes. The different morphologies are obtained by varying the addition time of LCM, temperature, solvent ratio, and monomer ratio. The microgel morphologies are characterized by (cryogenic) transmission and scanning electron microscopy. The thermoresponsiveness is investigated by dynamic light scattering (DLS), while the incorporation of LCM into the microgel structure is determined via H-NMR and Raman spectroscopy. The experimental data indicate that adjusting reaction conditions enables the fabrication of microgels with various morphologies. Finally, their capability to solubilize hydrophobic substances is demonstrated by successfully facilitating the uptake of the hydrophobic dye Nile Red (NR).
了解和控制微凝胶的形态对于优化其在不同应用领域的性能和功能至关重要。采用无模板方法制备具有结构和化学各向异性的微凝胶面临重大挑战。现有的制备此类微凝胶的方法通常局限于低通量的模板法。在此，开发了一种自下而上的替代方法，通过半间歇沉淀聚合法制备基于N-乙烯基己内酰胺（VCL）的非球形微凝胶，并引入具有液晶（LC）部分的功能性共聚单体。4-甲氧基苯甲酸4-(6-丙烯酰氧基己氧基)苯酯（LCM）用作LC共聚单体。所得微凝胶的形态可调整为多叶状、哑铃状和覆盆子状。通过改变LCM的添加时间、温度、溶剂比例和单体比例可获得不同的形态。通过（低温）透射电子显微镜和扫描电子显微镜对微凝胶形态进行表征。通过动态光散射（DLS）研究其热响应性，同时通过1H-NMR和拉曼光谱确定LCM在微凝胶结构中的掺入情况。实验数据表明，调整反应条件能够制备出具有各种形态的微凝胶。最后，通过成功促进疏水性染料尼罗红（NR）的摄取，证明了它们溶解疏水性物质的能力。
