利用原子力显微镜测量复合微胶囊静态弹性性质

Measurement of the static elastic properties of composite microcapsules using atomic force microscopy

用层-层组装方法制备了直径约为6μm的聚电解质多层复合微囊,并用原子力显微镜研究了微囊的弹性性质。通过用微球修饰的原子力显微镜探针对微囊加载,在空气和水环境下测量了不同刚性探针加载液体填充微囊的力曲线,利用微囊变形理论模型拟合力曲线,得到多层微胶囊的杨氏模量在90MPa^180MPa之间。

The composite multiplayer polyelectrolyte capsules with size around 6 μm were fabricated using layer by layer self-assembly method. The elastic properties of the capsule were studied by atomic force microscopy. The capsule was pressed by cantilever of different lengths, with a glass bead glued on the end of the cantilever. The force curves were measured on capsules in air and water environments. Within these capsules the liquid was enveloped. The force curves were fitted based on a shell deformation model, and the Young＇s module of the multiplayer polyelectrolyte microcapsule between 90 MPa - 180 MPa was obtained. Results show that this model can predict the elastic deformation of the microcapsule in the force range beyond 5 nN. The accuracy of the elastic deformation of polymer capsule can be ensured using the cantilever of mediate stiffness.