Langmuir–Scheaffer Technique as a Method for Controlled Alignment of 1D Materials

Abstract

A widely applicable method for aligning 1D materials, and in particular carbon nanotubes (CNTs), independent of their preparation would be very useful as the growth methods for these materials are substance-specific. Langmuir−Schaefer (LS) deposition could be such an approach for alignment, as it aligns a large number of 1D materials independently of the desired substrate. However, the mechanism and required conditions for alignment of 1D nanomaterials in a Langmuir trough are still unclear. Here we show, relying on numerical simulations of the Langmuir film compression, that the LS method is a powerful tool to achieve maximal alignment of 1D material in a controllable manner. In particular, 1D materials terminated with a suitable surfactant can align only if the velocity induced by the attraction between individual 1D entities is low enough relative to the flow speed. To validate this model, we achieved an efficient LS alignment of single-walled carbon nanotubes covered with a suitable surfactant relying on the numerical simulations. In situ polarized Raman microspectroscopy during the compression of Langmuir film revealed good quantitative agreement between the numerical simulations and the experiment. This suggests the applicability of the LS technique as a versatile method for the controlled alignment of 1D materials.

Aligned Bilayer of Single-Walled Carbon Nanotubes Suppresses the Polysulfide Shuttle in Li–S Batteries

“…Furthermore, when the polarization of the excitation laser is parallel to the alignment of the SWCNTs, the intensity of the G-band is higher compared to the situation when the polarization of the laser is perpendicular to the alignment of the SWCNTs . Quantitatively, an orientation parameter can be calculated and compared to the simulated data for aligned SWCNTs in Langmuir films, which we accomplished in our previous work . It is important to note that the extinction of G-band intensity is incomplete, suggesting an imperfect alignment degree of SWCNTs in our films.…”

“…28 Quantitatively, an orientation parameter can be calculated and compared to the simulated data for aligned SWCNTs in Langmuir films, which we accomplished in our previous work. 22 It is important to note that the extinction of G-band intensity is incomplete, suggesting an imperfect alignment degree of SWCNTs in our films. As will be shown later, this incomplete extinction is primarily due to bent segments in long SWCNTs.…”

Nanofabrication Techniques in Large-Area Molecular Electronic Devices

“…In addition to the typical amphiphilic molecules described above, the LB technique is largely enlarged towards the assembly of more complex structures with interest in molecular electronics (and organic electronics). Polymers [281][282][283], metalloporphyrines [284], DNA [285], perylenes [286], perylene-NH 2 [287], ruthenium complexes [288], organo-modified inorganic nanoparticles in combination with polymer nanospheres (nano-mille-feuille system) [289], pillar [5]arene derivatives [290], polymer-coated CsPbBr 3 nanowires [291], aligned SWCNTs [145], semi-conductive 2D materials based on 2,3,6,7,10,11-hexaiminotriphenylene (HATP) [292], or rGO [146] have been used.…”

Modulated Fluorescence in LB Films Based on DADQs—A Potential Sensing Surface?

“…LB films can be engineered for numerous applications including functional coatings, sensing surfaces, etc. [1][2][3][4][5][6][7][8][9][10][11], but LB films also resemble naturally occurring biological cell membranes. Despite widespread applications, there are, to our knowledge, very few examples of fluorescent LB films.…”