Kocun Marta, Labuda Aleksander, Gannepalli Anil, Proksch Roger
Asylum Research, an Oxford Instruments Company, Santa Barbara, California 93117, USA.
Rev Sci Instrum. 2015 Aug;86(8):083706. doi: 10.1063/1.4928105.
Contact Resonance Force Microscopy (CR-FM) is a leading atomic force microscopy technique for measuring viscoelastic nano-mechanical properties. Conventional piezo-excited CR-FM measurements have been limited to imaging in air, since the "forest of peaks" frequency response associated with acoustic excitation methods effectively masks the true cantilever resonance. Using photothermal excitation results in clean contact, resonance spectra that closely match the ideal frequency response of the cantilever, allowing unambiguous and simple resonance frequency and quality factor measurements in air and liquids alike. This extends the capabilities of CR-FM to biologically relevant and other soft samples in liquid environments. We demonstrate CR-FM in air and water on both stiff silicon/titanium samples and softer polystyrene-polyethylene-polypropylene polymer samples with the quantitative moduli having very good agreement between expected and measured values.
接触共振力显微镜（CR-FM）是一种用于测量粘弹性纳米力学性能的领先原子力显微镜技术。传统的压电激发CR-FM测量仅限于在空气中成像，因为与声激发方法相关的“峰林”频率响应有效地掩盖了真正的悬臂梁共振。使用光热激发可实现清晰的接触，共振光谱与悬臂梁的理想频率响应紧密匹配，从而能够在空气和液体中进行明确且简单的共振频率和品质因数测量。这将CR-FM的功能扩展到了液体环境中的生物相关及其他软样品。我们在空气和水中对刚性硅/钛样品以及较软的聚苯乙烯-聚乙烯-聚丙烯聚合物样品进行了CR-FM测试，定量模量的预期值与测量值之间具有非常好的一致性。
