Vapor-Condensation-Assisted Optical Microscopy for Ultralong Carbon Nanotubes and Other Nanostructures

Abstract

Here we present a simple yet powerful approach for the imaging of nanostructures under an optical microscope with the help of vapor condensation on their surfaces. Supersaturated water vapor will first form a nanometer-sized water droplet on the condensation nuclei on the surface of nanostructures, and then the water droplet will grow bigger and scatter more light to make the outline of the nanostructure be visible under dark-field optical microscope. This vapor-condensation-assisted (VCA) optical microscopy is applicable to a variety of nanostructures from ultralong carbon nanotubes to functional groups, generating images with contrast coming from the difference in density of the condensation sites, and does not induce any impurities to the specimens. Moreover, this low-cost and efficient technique can be conveniently integrated with other facilities, such as Raman spectroscope and so forth, which will pave the way for widespread applications.

True-color real-time imaging and spectroscopy of carbon nanotubes on substrates using enhanced Rayleigh scattering

“…Combining Rayleigh and Raman spectra, the chiral indices of the six individual SWCNTs in Figs. 4(a) and 4(b) are assigned as (16,12), (17,12), (22,3), (13,9), Nano Res. (17,16), and (20, 6), respectively.…”

“…In these cases, the strong tube-tube interactions might lead to a shift in peak positions compared to isolated SWCNTs [22,23]. Rayleigh spectra of all six individual nanotubes in (a) from left to right in order, whose chiral indices were identified as (16,12), (17,12), (22,3), (13,9), (17,16), and (20, 6), respectively. (i)-(k) Raman spectra of the three SWCNTs whose Rayleigh spectra are shown in (e)-(g) respectively.…”

“…Unfortunately most nanomaterials, such as SWCNTs, are invisible under an ordinary optical microscope because of the extremely small Rayleigh scattering cross-sections of nanomaterials and the low intensity of excitation light. A general approach to this problem is to decorate the nanomaterials with some micrometer sized particles serving as scattering centers, such as solid microparticles [9][10][11] or water microdroplets [12]. Another approach is to use fluorescence microscopy, which enables imaging of bio-nanomaterials functionalized by fluorescence proteins under an optical microscope with laser illumination [13][14][15].…”

Optical visualization and polarized light absorption of the single-wall carbon nanotube to verify intrinsic thermal applications

“…Compared with the previous methods, in our strategy, the visualization process is reversible because the nanotube will recover to its naked form without any change in structure when it returns to room temperature (proven by comparing the TEM feature and ED pattern before and after the melting process). Very recently, Wang et al developed a technique to observe nanostructures using an optical microscope with water vapor condensation 28 . Here, we want to point out that in our method, the nanotube attached to the substrate can also be reversibly visualized probably because ice nucleation was facilitated by the nanotubes in comparison to the surrounding flat substrate.…”

Roll-to-Roll Microcontact Printing of Flexible Aluminum Substrates Using Octadecylphosphonic Acid (ODPA)

“…More casually the existence of SAM patterns can be quickly visualized by condensing one's breath on the surface and seeing a pattern as the condensate evaporates. This method has been examined formally to enhance visualization of CNT and other nano-structures by Wang et al [23].…”