Examining sensitivity to tip-sample interaction forces in biharmonic and bimodal AFM under acoustic emissions in air and liquids

Yılmaz Ç.

3rd Emerging Technologies in Mechanical Engineering, Gangwon-Do, Güney Kore, 10 - 12 Aralık 2025, ss.1, (Özet Bildiri)

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: Gangwon-Do
  • Basıldığı Ülke: Güney Kore
  • Sayfa Sayıları: ss.1
  • Akdeniz Üniversitesi Adresli: Evet

Özet

Multi-frequency excitation schemes are applied to resonate the micro-cantilever for enhanced sensitivity to tip-sample interaction forces in AFM. During AFM operations, external forces such as acoustic forces act on the micro-cantilevers, thereby affecting their oscillating responses in different operating mediums. Thus, the hydrodynamic loads owing to the fluidic mediums and the influences of acoustic emissions on the behaviors of the micro-cantilever are to be considered for accurate quantification of sensitivity to tip-sample interaction forces. This paper presents theoretical research performed to explore the vibrating behaviors of the periodically driven micro-cantilever under van der Waals forces in methanol and ethylacetate mixtures. Dynamic acoustic forces are assumed to act on the one-side area of the micro-cantilever, actuated using biharmonic and bimodal excitation schemes. For particular operating conditions, responses of the proposed dynamic model are compared with the experimental results given in the literature, and the numerical results demonstrate good agreement with the AFM measurements. It is also indicated that application of biharmonic excitations yields notable enhancements in sensitivity of amplitude, phase shift, and frequency shift at the particular separation distances below 10 nm in air, when compared with the bimodal operations. Moreover, vibration observables considerably change at the lower separation distance where the nonlinear effect of van der Waals force is quite larger, as the strength and frequency of the acoustic force increases in air. On the other hand, the micro-cantilever does not exhibit remarkable sensitivity to acoustic and hydrodynamic loads in different methanol and ethylacetate mixtures owing to the higher damping effect. Therefore, the effects of acoustic emissions on the micro-cantilever dynamics are to be considered for precise quantification of tip-sample interaction forces during multi-frequency AFM operations in air.