Sahin Ozgur, Erina Natalia
The Rowland Institute at Harvard, Harvard University, Cambridge, MA 02142, USA.
Nanotechnology. 2008 Nov 5;19(44):445717. doi: 10.1088/0957-4484/19/44/445717. Epub 2008 Oct 2.
High spatial resolution imaging of material properties is an important task for the continued development of nanomaterials and studies of biological systems. Time-varying interaction forces between the vibrating tip and the sample in a tapping-mode atomic force microscope contain detailed information about the elastic, adhesive, and dissipative response of the sample. We report real-time measurement and analysis of the time-varying tip-sample interaction forces with recently introduced torsional harmonic cantilevers. With these measurements, high-resolution maps of elastic modulus, adhesion force, energy dissipation, and topography are generated simultaneously in a single scan. With peak tapping forces as low as 0.6 nN, we demonstrate measurements on blended polymers and self-assembled molecular architectures with feature sizes at 1, 10, and 500 nm. We also observed an elastic modulus measurement range of four orders of magnitude (1 MPa to 10 GPa) for a single cantilever under identical feedback conditions, which can be particularly useful for analyzing heterogeneous samples with largely different material components.
材料特性的高空间分辨率成像对于纳米材料的持续发展和生物系统研究而言是一项重要任务。在轻敲模式原子力显微镜中，振动探针与样品之间的时变相互作用力包含有关样品弹性、粘附性和耗散响应的详细信息。我们报告了使用最近推出的扭转谐波悬臂对时变探针 - 样品相互作用力进行的实时测量和分析。通过这些测量，在单次扫描中可同时生成弹性模量、粘附力、能量耗散和形貌的高分辨率图谱。在峰值轻敲力低至0.6 nN的情况下，我们展示了对特征尺寸为1、10和500 nm的共混聚合物和自组装分子结构的测量。我们还观察到，在相同反馈条件下，单个悬臂的弹性模量测量范围可达四个数量级（1 MPa至10 GPa），这对于分析具有很大不同材料成分的异质样品可能特别有用。
