In situ characterization on macroscale 3D spatial dispersion of MWCNTs in matrix and interfacial phases of quartz fibers/epoxy composites via fluorescence imaging

Confining Fluorescence Detection for Distinguishable Visualization of Multivariate Nanoparticles: Implications for Design and Controllable Preparation of Nanocomposites

“…The results not only demonstrated the successful grafting of FITC fluorescent molecules but also represented the effective protection effect of the PGMA layer on preventing FITC fluorescence quenching by isolating the transition of electrons between carbon tubes and fluorescent molecules. 18,37 Pristine GO-COOH had the ability to produce broadband fluorescence under excitation due to its oxygen-containing functional groups and defects, 38 resulting in a faint emission peak (Figure 2c 3 ), while f-GO had a strong fluorescence emission peak at 428 nm, which directly proved the successful preparation of NH 2 -COUR-labeled GO. Similar to f-MWCNTs, the PGMA layer covering on GO-COOH also acted as the protection to avoid the fluorescence quenching caused by the photo-induced electron transfer process.…”

“…26 Then, SiO 2 -NH 2 was dispersed in an ethanol solution containing rhodamine B (RhoB) and reacted at 50 °C in the dark for 24 h to obtain fluorescent silica (f-SiO 2 ) with red lightemitting properties under 520 nm excitation. 27 In reference to our earlier works, 18,28,29 the fluorescently labeled carbon nanotubes (f-MWCNTs) were synthesized in the following procedures. First, the MWCNT surface was initially coated with a PGMA layer (MWCNTs-PGMA) by in situ surface-initiated atom transfer radical polymerization (ATRP) of GMA.…”

“…Figure 2a 2 shows the FTIR spectra of MWCNTs-COOH and the products after each step of grafting modification. According to our previous research, 18 the PGMA protective layer was first grafted on MWCNTs-COOH by ATRP reaction, and then the fluorescent molecule FITC was introduced. The characteristic peak of the C�S group at 1465 cm −1 in Figure 2a 2 proved the successful preparation of FITC-labeled f-MWCNTs.…”

“…The dispersion of fluorescent nanoparticles in multivariate nanoreinforced composites was calculated by Morisita's index (I) and particle spacing probability density theory in reference to our previous work. 18 RhoB, FITC, and NH 2 -COUR fluorescent molecules were fully optimized by the hybrid B3LYP, in combination with the 6-31G(d) basis set. The excited-state characteristics were calculated by time-dependent density functional theory (TD-DFT) using optimized ground-state geometries.…”

“…17 Furthermore, large-scale visualization was performed in our previous work for the dispersion evolution behaviors of carbon nanotubes (CNTs) in the matrix and at the fiber/resin interfaces, as well as for the quantitative investigation on the correlation between curing temperatures and CNT dispersion. 18 Although large-scale visualization methods for unitary nanoparticles in the matrix were well established based on CLSM technology, to the best of our knowledge, those for the large-scale 3D dispersion of multivariate nanoparticles and microstructural networks produced between themselves were still lacking. The essential for visualizing nanoparticle dispersion was fluorescent labeling, which endowed nanoparticles with controllable fluorescence properties for CLSM imaging.…”