Polydispersity and assembling phenomena of native and reactive dye-labelled nanocellulose

Abstract

The assembling (self-association vs. aggregation or agglomeration) of highly polydispersed nanocelluloses (NCs) is a well-known but difficult to identify phenomena. In this research complementary analytical tools were applied for tracking and assessing this phenomena under different conditions (base vs. buffer) using both native and dye-labelled cellulose nanofibrils (CNFs) and cellulose nanocrystals. For this purpose, dichlorotriazine-type reactive blue 4 (RB4) dye was covalently (through alkyl-aryl ether bond) and regioselectively (to C6-OH groups) attached to the NC, being identified by ATR-FTIR and 13 C CP/ MAS solid-state NMR spectroscopies, and quantified by UV-Vis spectroscopy. The introduced RB4's anthraquinone (i.e. hydrophobic) moieties evoked aggregation of those CNFs being quantified from the shifting and broadening of size-distribution profiles within differential light scattering analysis and their fpotential reduction. In addition, their high polydispersity profiles was assessed by qualitatively supported differential centrifugal sedimentation, nanoparticle tracking analysis, and transmission electron microscopy. A desorption of chemically non-bonded, yet highly substantive (i.e. partially or fully hydrolysed), dye from both types of NCs was also identified by capillary electrophoresis, which simultaneously excluded the non-labelled fractions, thus obtaining free dye-absent NC dispersions. Finally, labelling extent-triggered separation within the RB4-labelled CNFs was identified by applying the micellar capillary electrophoresis, thus confirming the conformational changes affecting NCs' hydrodynamic (size) profiles.

Making polymers colored and stiffer by dyed regenerated cellulose employing Pickering emulsions

“…Compared with RC, the chemical shift of the amorphous region (59.92 ppm) of C6 in DRC was obvious, increasing by 0.64 ppm, which was caused by the resonance up-shift effect of adjacent carbon during the hydroxyl modification, indicating that the dye was grafted on the RC. Similar observations upon chemical modification of cellulose were reported previously [18]. The dye fixation is 16.6 %.…”

Internalization of (bis)phosphonate-modified cellulose nanocrystals by human osteoblast cells

“…1a) was performed to verify the success of CNCs' modifications. A typical spectral line corresponding to the cellulose can be observed for native CNCs (Gorgieva et al 2015). Namely, the C-O stretching vibration of the cellulose glucose ring at 1031 cm −1 , as well as the broad peaks centred at about 3338 and 2901 cm Since the banding vibration of water at around 1640 cm −1 has a pronounced shielding effect over the carbonyl region (Qojewska et al 2005), being important for the verification of the modification, the latter was deconvoluted using the PeakFit 4.12 programme (Fig.…”

“…The zeta-potential and zeta-size analysis of native and differently modified CNC dispersions were carried by Zeta-sizer (Nano ZS ZEN360, Malvern Instruments Ltd., UK) at 20 ± 0.1°C using the cell ZEN1010, applying the following parameters: A material refractive index of 1.47, dispersion refractive index of 1.33, and viscosity of 0.8872 cP (Gorgieva et al 2015). A field of 40 V was applied across the nominal electrode spacing of 16 mm.…”

Alkaline membrane fuel cells: anion exchange membranes and fuels

“…Cellulose is the most abundant natural, biodegradable and bio-renewable material with low weight, low density, exceptional mechanical properties and functionalisation potential, as it contains many OH groups. 141 Different types of nanocellulose are differentiated by the production processes, and include nanocrystalline cellulose (CNC), nanobrillar cellulose (CNF) and bacterial cellulose (BC), characterised by different morphology, particle size, crystallinity, etc. CNFs consist of long brils with a diameter between 1-100 nm and a length of 500-2000 nm, high surface area and interchanging crystalline and amorphous regions.…”