Abstract
One key component in the assembly of nanoparticles is their precise positioning to enable the creation of new complex nano-objects. Controlling the nanoscale interactions is crucial for the prediction and understanding of the behaviour of nanoparticles (NPs) during their assembly. In the present work, we have manipulated bare and functionalized gold nanoparticles on flat and patterned silicon and silicon coated substrates with dynamic atomic force microscopy (AFM). Under ambient conditions, the particles adhere to silicon until a critical drive amplitude is reached by oscillations of the probing tip. Beyond that threshold, the particles start to follow different directions, depending on their geometry, size and adhesion to the substrate. Higher and respectively, lower mobility was observed when the gold particles were coated with methyl (–CH3) and hydroxyl (–OH) terminated thiol groups. This major result suggests that the adhesion of the particles to the substrate is strongly reduced by the presence of hydrophobic interfaces. The influence of critical parameters on the manipulation was investigated and discussed viz. the shape, size and grafting of the NPs, as well as the surface chemistry and the patterning of the substrate, and finally the operating conditions (temperature, humidity and scan velocity). Whereas the operating conditions and substrate structure are shown to have a strong effect on the mobility of the particles, we did not find any differences when manipulating ordered vs random distributed particles.
Highlights
Nanotechnology, which aims at the ideal miniaturization of devices and machines down to atomic and molecular sizes has become a strategic topic with a promising future in high technology for the forthcoming century [1]
Spherical and asymmetrical gold nanoparticles were synthesized as described in the Experimental section and deposited where Apiezo is the oscillation amplitude of a piezo-element coupled to the cantilever, f0, k and Q are the resonance frequency, the spring constant and the quality factor of the free cantilever, respectively, and is the phase shift caused by the interaction between the tip and the underlying particles or surface
We have described manipulation of gold colloidal nanoparticles using atomic force microscopy (AFM) in tapping mode
Summary
Nanotechnology, which aims at the ideal miniaturization of devices and machines down to atomic and molecular sizes has become a strategic topic with a promising future in high technology for the forthcoming century [1]. Nanometer scale antimony particles have been manipulated on an atomically flat graphite surface by atomic force microscopy techniques and quantitative information on interfacial friction was extracted from the lateral manipulation of these nanoparticles [17]. Sitti and coworkers have manipulated nanoscale latex particles positioned on Si substrates with an accuracy of about 30 nm [20] whilst Mougin et al manipulated as-synthesized and functionalized gold nanoparticles on silicon substrates with dynamic AFM [21] In all these techniques, the major difficulties that arise are related to the quantification of the dynamical processes occurring during manipulation, i.e., collisions between probing tips and particles, friction between particles and substrates, electrostatic interactions among all of them, etc. Conclusions with discussions and future directions are given in the last paragraph
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
