Fast and non-destructive Raman spectroscopic determination of multi-walled carbon nanotube (MWCNT) contents in MWCNT/polydimethylsiloxane composites

Abstract

A versatile Raman spectroscopic method to determine the contents of carbon nanotubes (CNTs) in CNT/polydimethylsiloxane (PDMS) composites is demonstrated, and important issues directly related to the accuracy of the measurement have been investigated. Initially, Raman microscopic mappings over an area of 6.0 × 6.0 mm were carried out on CNT/PDMS composites, which revealed the existence of the partial localization of CNTs on a microscopic scale. Therefore, a laser illumination scheme covering a large sample area of 28.3 mm was employed to acquire a sample spectrum representative of the whole CNT concentration. The peak area ratio between the CNT and PDMS peaks clearly varied with the CNT concentration, whereas the reproducibility of measurements was degraded for the composites containing more than 3.0 wt% CNTs because of the decreased Raman sampling volume arising from the absorption of laser radiation by the CNTs. The laser penetration depth was semi-quantitatively investigated by observing the spectra of thin-sliced samples collected by positioning a Teflon disk behind the sample, and Monte Carlo simulations were employed to examine the internal photon propagation as well as explain the experimental observation. In summary, the fundamental issues affecting the Raman measurement of the CNT containing polymer matrix have been clearly addressed, and the finding here will be a beneficial basis for successful Raman spectroscopic analysis of different CNT-containing composites.

Fabrication of Multiwalled Carbon Nanotubes (MWCNT) and Reduced Graphene Oxide (rGO)‐based thermoplastic polyurethane and polypyrrole nanocomposites for electromagnetic wave absorption application with a low reflection

“…Moreover, 2d peaks are observed at 2668 cm −1 , and a D + G peak appeared at 2931 cm −1 27,28 . MWCNT of Raman spectra shows a D peak at 1323 cm −1 and a G peak at 1600 cm −1 , indicating the disorder‐induced characteristics of MWCNT and the Raman‐active in‐plane atomic displacement E 2g mode, respectively 29 . The I D / I G ratio of rGO is 0.841 30 .…”

“…27,28 MWCNT of Raman spectra shows a D peak at 1323 cm À1 and a G peak at 1600 cm À1 , indicating the disorder-induced characteristics of MWCNT and the Raman-active in-plane atomic displacement E 2g mode, respectively. 29 The I D /I G ratio of rGO is 0.841. 30 Additionally, with a rise in rGO and MWCNT php, the D and G peaks are shifted, indicating the enhancement of interfacial interaction between rGO or MWCNT nanofiller and TPU matrix.…”

“…and MWCNT (0.5 php) in both nanocomposites. 29 The blue shift in the D band arises because of the migration of C C bonds in the carbon plane of the rGO phase, which results from the interaction in terms of hydrogen-bonding between the carboxyl ( COOH) and hydroxyl ( OH) groups of rGO and the OH groups of the TPU phase, whereas the shift in G band shifting is mostly caused by π-π interactions, leading to increased doping levels. 31 The expected interaction between the different components is shown in Scheme 2.…”

3D Printable One‐Part Carbon Nanotube‐Elastomer Ink for Health Monitoring Applications

“…The D-peaks at 1350 cm −1 demonstrate the sp 3 hybridized carbons or amorphous carbon structures. [49,50] The G-peaks at 1575 cm −1 represent the sp 2 hybridized carbons that make up the backbone of the carbon nanotubes. [49,50] As evidenced by the amplitudes of the peaks for 1% CNT-silicone versus 10% CNT-silicone, the intensity of the D-and G-peaks increased with increasing concentration.…”

“…[49,50] The G-peaks at 1575 cm −1 represent the sp 2 hybridized carbons that make up the backbone of the carbon nanotubes. [49,50] As evidenced by the amplitudes of the peaks for 1% CNT-silicone versus 10% CNT-silicone, the intensity of the D-and G-peaks increased with increasing concentration. The peaks near 2900 cm −1 indicate the structure of silicone is not changed in the fabrication process from 1% to 10% CNT loading.…”