Dip-pen nanolithography (DPN) is a scanning probe microscopy-based nanofabrication
method that relies on a fluid-coated atomic force microscope probe for the
deposition of material on a substrate with nanometer-scale resolution. The ability to
tailor the structure and chemical composition of materials at the nanometer length
scale is enabling in elds ranging from medical diagnostics to nano-electronics. While
DPN is among the highest resolution additive manufacturing techniques to date, the
conguration of ink on the probe and the process of ink transport are poorly understood.
Specically, the inking and patterning procedures are susceptible to variations
in the ambient environmental conditions and currently not all aspects of the processes
are reliably controlled. Thus, a key challenge barring the widespread adoption
of DPN beyond a research tool is reproducibility. We hypothesize that closed-loop
control over the inking and patterning process could address this irreproducibility,
however techniques to monitor the quantity and concentration of ink on the tip of the
probe have not been yet developed. Here, we study the mechanics of atomic force microscope
(AFM) probes throughout the inking and patterning process to understand
if the behavior of the ink can be studied in situ. In particular, we develop an approach
for conning ink to the tip of an AFM probe, which is critical for reliable patterning
and modeling the mechanics of the probe. Then, we nd that the quantity of ink
on an AFM probe can be determined in situ by observing the shift in the natural
frequency of the probe. Finally, we show that this method allows for the observation
and quantication of the ink deposited on a substrate, in real time. Collectively,
these approaches lay the groundwork for a closed-loop implementation of DPN in
which the inking and patterning processes are performed with drastically improved
reliability. Given that these techniques are easily implemented on any commercial
AFM, we expect that they could lead to new applications in the study of nanoscale
soft materials. / 2017-11-04T00:00:00Z
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/19498 |
| Date | 05 November 2016 |
| Creators | Farmakidis, Nikolaos |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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