Using cellulose nanofibers isolated from waste hop stems to stabilize dodecane or olive oil-in-water Pickering emulsions

Kanai, Noriko; Sakai, Takahiro; Yamada, Kazutoyo; Kumagai, Sari; Kawamura, Izuru

doi:10.1016/j.colsurfa.2022.129956

Cited by 12 publications

(14 citation statements)

References 52 publications

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“…Our previous study reported that the mean diameter of oil droplets on day 1 was 4.8 μm for 1.0% d-CNF, 7.6 μm for 0.5% d-CNF, 6.9 μm for 1.0% o-CNF, and 7.9 μm for 0.5% o-CNF. 15 Specifically for the d-CNF emulsions, a droplet-depleted serum layer (i.e., water) appeared on day 7 for the 0.5% CNF, whereas on day 31 for 1.0%. The thickness of the transparent serum layer slightly expanded over time in the d-CNF emulsions.…”

Section: ■ Results and Discussionmentioning

confidence: 93%

“…Our previous studies using confocal laser scanning microscopy showed rapid droplet growth in o-CNF emulsions with droplets larger than several tens of micrometers. 15 The serum layer at the bottom was also distinguished in bright contrast in the d-CNF emulsions in both FLASH and RARE. The average thickness of the serum layer was 1.8 mm for 0.5% and 0.6 mm for 1.0% on day 31.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

“…TEMPO-oxidized CNFs (1.0%) were isolated from airdried and mechanically milled HS following the previously reported protocols: the median height of the individualized CNF was 1.7 ± 0.7 nm from AFM observations. 15 Also, the carboxylate content of the obtained CNF determined from conductometric titration was 0.59 mmol g −1 . 25 The 1.0% dispersion and a 0.5% dispersion prepared by dilution with distilled water were sonicated for 1.5 min just before preparing emulsions using an ultrasonic processor (Qsonica, Q700) in the pulse mode with a maximum amplitude (i.e., tip excursion) of 134 μm.…”

Section: Sample Preparation Isolation Of Tempo-oxidized Cellulosementioning

confidence: 98%

“…Cellulose nanofibers (CNFs) are promising emulsifiers for Pickering emulsions offering amphiphilic character, biocompatibility, and sustainability. − Several works demonstrated that surface-carboxylated CNFs by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) exhibited higher stability than unmodified CNFs owing to the negative surface charge. − Fujisawa et al reported that the cellulose origin should not significantly impact the formation of Pickering emulsions. Inspired by their research, we previously studied TEMPO-oxidized CNFs isolated from agricultural waste hop stems (HS) as an emulsifier for oil-in-water Pickering emulsions using dodecane or olive oil as the oil . A notable difference in physicochemical properties (e.g., droplet size distribution) was found when using the two different types of oils (i.e., single- or multicomponent).…”

Section: Introductionmentioning

confidence: 99%

“…Inspired by their research, we previously studied TEMPOoxidized CNFs isolated from agricultural waste hop stems (HS) as an emulsifier for oil-in-water Pickering emulsions using dodecane or olive oil as the oil. 15 A notable difference in physicochemical properties (e.g., droplet size distribution) was found when using the two different types of oils (i.e., single-or multicomponent). However, the opacity of the emulsions limited the use of microscopy to evaluate the instability mechanisms.…”

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confidence: 99%

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Evaluating the Stability of Cellulose Nanofiber Pickering Emulsions Using MRI and Relaxometry

et al. 2023

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Magnetic resonance imaging (MRI) relaxometry and diffusion methods were used to highlight the instability mechanisms of oil-in-water Pickering emulsions stabilized by cellulose nanofibers (CNFs). Four different Pickering emulsions using different oils (n-dodecane and olive oil) and concentrations of CNFs (0.5 and 1.0 wt %) were systematically investigated over a period of one month after emulsification. The separation into a free oil, emulsion layer, and serum layer and the distribution of flocculated/coalesced oil droplets in several hundred micrometers were captured in MR images using fast low-angle shot (FLASH) and rapid acquisition with relaxation enhancement (RARE) sequences. The components of the Pickering emulsions (e.g., free oil, emulsion layer, oil droplets, and serum layer) were observable by different voxelwise relaxation times and apparent diffusion coefficients (ADCs) and reconstructing in the apparent T 1, T 2, and ADC maps. The mean T 1, T 2, and ADC of the free oil and serum layer corresponded well with MRI results for pure oils and water, respectively. Comparing the relaxation properties and translational diffusion coefficients of pure dodecane and olive oil obtained from NMR and MRI resulted in similar T 1 and ADC but significantly different T 2 depending on the sequence used. The diffusion coefficients of olive oil measured by NMR were much slower than dodecane. The ADC of the emulsion layer for dodecane emulsions did not correlate with the viscosity of the emulsions as the CNF concentration increased, suggesting the effects of restricted diffusion of oil/water molecules due to droplet packing.

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Section: ■ Results and Discussionmentioning

confidence: 93%

Section: ■ Results and Discussionmentioning

confidence: 96%

Section: Sample Preparation Isolation Of Tempo-oxidized Cellulosementioning

confidence: 98%