Impact of wormlike micelles on nano and macroscopic structure of TEMPO-oxidized cellulose nanofibril hydrogels

Silva, Marcelo da; Calabrese, Vincenzo; Schmitt, Julien; Hossain, Kazi M. Zakir; Bryant, Saffron J.; Mahmoudi, Najet; Scott, Janet L.; Edler, Karen J.

doi:10.1039/d0sm00135j

Cited by 8 publications

(8 citation statements)

References 55 publications

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“…This was observed for all mixtures of OCNF with Laponite, and for some mixtures with montmorillonite (see Supporting information ). This overshoot has been observed previously by our group for OCNF [ 34 , 35 ]. Strain thickening such as this is a result of resistance that comes about due to deformation of the system.…”

Section: Resultssupporting

confidence: 83%

“…Strain thickening such as this is a result of resistance that comes about due to deformation of the system. For example, deformation of the OCNF network may lead to orientation which is combatted by repulsive electrostatic forces [ 35 ]. Similar behaviour has been observed in other systems, such as xanthan gum [ 36 ] and branched polymers [ 37 ].…”

Section: Resultsmentioning

confidence: 99%

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Rheological modification of partially oxidised cellulose nanofibril gels with inorganic clays

et al. 2021

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This study aimed to quantify the influence of clays and partially oxidised cellulose nanofibrils (OCNF) on gelation as well as characterise their physical and chemical interactions. Mixtures of Laponite and montmorillonite clays with OCNF form shear-thinning gels that are more viscous across the entire shear range than OCNF on its own. Viscosity and other rheological properties can be fine-tuned using different types of clay at different concentrations (0.5–2 wt%). Laponite particles are an order of magnitude smaller than those of montmorillonite (radii of 150 Å compared to 2000 Å) and are therefore able to facilitate networking of the cellulose fibrils, resulting in stronger effects on rheological properties including greater viscosity. This work presents a mechanism for modifying rheological properties using renewable and environmentally-friendly nanocellulose and clays which could be used in a variety of industrial products including home and personal care formulations.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Rheological modification of partially oxidised cellulose nanofibril gels with inorganic clays

et al. 2021

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“…The positive choline ions would associate with the negative micelles with the ability to bridge between micelles [11]. The length of the cylinders, relatively short compared to SDS-in-water cylindrical aggregates (wormlike micelles, l > 1000 Å [36,37]), is consistent with the choline ions bridging and linking 2 -3 spherical micelles in forming cylindrical micelles.…”

Section: Further Discussion and Concluding Remarksmentioning

confidence: 89%

Morphological Transformation of SDS Aggregates in a Deep Eutectic Solvent Above the Fracto-eutectogel to Fluid Transition Temperature

Matthews¹,

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Se³

et al. 2021

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Understanding surfactant self-assembly in deep eutectic solvents (DES) is important to their potential use in industrial formulations. We have recently reported the formation of a fracto-eutectogel comprising SDS fractal aggregates at a concentration as low as 1.6 wt% in glyceline (a DES comprising glycerol and choline chloride) at room temperature. The building units of the fractals consisted of multilayers of self-assembled SDS lamellae arranged in a dendritic pattern. Here we report that this fractal phase transitions into a fluid phase above a critical gelation temperature, TCG ~ 45 oC, evident from polarized light microscopy (PLM) observations. Small-angle neutron scattering (SANS) reveals that this phase transition is underpinned by the nanoscopic morphological transformation of the SDS lamellae into cylindrical micelles at T &gt; TGC. Fitting SANS profiles confirms that the morphology of the micelles is SDS-concentration (cSDS) dependent at T &gt; TGC: cylindrical at cSDS &gt; 0.6 wt% and spherical at cSDS = 0.6 wt%. At cSDS &lt; 0.6 wt%, only isotropic scattering was observed in the SANS profiles. Such SDS self-assembly behaviors contrast with those we have previously observed in glycerol, which we attribute to the presence of ions (i.e. choline chloride) in glyceline. Our findings have general implications to surfactant self-assembly in DES, solvents that are rich in hydrogen bonding and ions.

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“…A stress-controlled rheometer (Discovery HR-3, TA Instruments, USA) equipped with a sandblasted plate-plate stainless steel geometry (40 mm) was used to perform the rheological tests at 25 • C, as previously described [15]. Gels (approximately 0.7 mL) were placed in between the plates and frequency, and amplitude sweeps and flow curves were measured (with a plate-plate gap of 0.5 mm).…”

Section: Rheological Analysismentioning

confidence: 99%

“…For example, 2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) mediated oxidation is commonly used to introduce negatively charged carboxyl groups to the cellulose surface, which is key to enhance the stability of particle dispersions in aqueous media due to electrostatic repulsion forces [4,5]. Cellulose nanofibrils have been extensively used to form hydrogels where the properties can be modulated by various factors such as salts [6,7], pH [8,9], concentration [10,11], temperature [12], and surfactants [13][14][15]. In addition, OCNF hydrogels have been reported to have excellent shear-thinning properties, which is desirable for 2 of 17 some formulation-based products, especially in health and personal care applications [13].…”

Section: Introductionmentioning

confidence: 99%

Monovalent Salt and pH-Induced Gelation of Oxidised Cellulose Nanofibrils and Starch Networks: Combining Rheology and Small-Angle X-ray Scattering

et al. 2021

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Water quality parameters such as salt content and various pH environments can alter the stability of gels as well as their rheological properties. Here, we investigated the effect of various concentrations of NaCl and different pH environments on the rheological properties of TEMPO-oxidised cellulose nanofibril (OCNF) and starch-based hydrogels. Addition of NaCl caused an increased stiffness of the OCNF:starch (1:1 wt%) blend gels, where salt played an important role in reducing the repulsive OCNF fibrillar interactions. The rheological properties of these hydrogels were unchanged at pH 5.0 to 9.0. However, at lower pH (4.0), the stiffness and viscosity of the OCNF and OCNF:starch gels appeared to increase due to proton-induced fibrillar interactions. In contrast, at higher pH (11.5), syneresis was observed due to the formation of denser and aggregated gel networks. Interactions as well as aggregation behaviour of these hydrogels were explored via ζ-potential measurements. Furthermore, the nanostructure of the OCNF gels was probed using small-angle x-ray scattering (SAXS), where the SAXS patterns showed an increase of slope in the low-q region with increasing salt concentration arising from aggregation due to the screening of the surface charge of the fibrils.

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Impact of wormlike micelles on nano and macroscopic structure of TEMPO-oxidized cellulose nanofibril hydrogels

Abstract: The shape of mixed surfactant micelles alters the rheological properties of TEMPO-oxidized cellulose nanofibril (OCNF) saline dispersions.

Cited by 8 publications

References 55 publications

Rheological modification of partially oxidised cellulose nanofibril gels with inorganic clays

Rheological modification of partially oxidised cellulose nanofibril gels with inorganic clays

Morphological Transformation of SDS Aggregates in a Deep Eutectic Solvent Above the Fracto-eutectogel to Fluid Transition Temperature

Monovalent Salt and pH-Induced Gelation of Oxidised Cellulose Nanofibrils and Starch Networks: Combining Rheology and Small-Angle X-ray Scattering

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