Synergistic Stabilization of Emulsions and Emulsion
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals
Synergistic Stabilization of Emulsions and Emulsion Gels with Water-Soluble Polymers and Cellulose Nanocrystals Zhen Hu, Tyler Patten, Robert Pelton, and Emily D. Cranston * Department of Chemical Engineering, McMaster University 1280 Main St. West, Hamilton, Ontario Canada L8S 4L7 * E-mail: [email protected] Number of pages: 6; number of figures: 8 Transmission Electron Microscopy (TEM). The anionic functional groups on CNC particles were selectively stained by mixing a 0.05 mL aliquot of the CNC (0.5 wt. %) with 0.5 mL of a 1 mM uranyl acetate solution and votexing the mixture for 2 min. A single drop of the stained suspension was dropped on a Formvar-coated copper TEM grid and dried for 4 h. TEM images were acquired using a JEOL 1200 EX TEMSCAN microscope operating at 80 kV.
Figure S1. TEM image of sulfated cellulose nanocrystals (CNCs). TEM image of CNCs is presented in Figure S1 and shows well-dispersed rod-shaped nanoparticles with average crystal dimensions of 128 × 7 nm. The average dimensions of these CNCs were determined by measuring the sizes of 100 individual nanocrystals.
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Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). CNC-coated sensors were prepared using an approach that has been previously used in a similar work. 1 Methyl cellulose (MC) adsorption on CNC surface was measured with an E4 QCM-D instrument from Q-Sense AB (Sweden) where the third, fifth, and seventh overtones were recorded. An aqueous solution of HEPES buffer was injected at a constant flow rate of 150 μL/min until the baseline frequency shift was less than 0.5 Hz over 10 min. Then 1 g/L MC in HEPES buffer was injected at 150 μL/min until the baseline was again stable, typically after 60 min. The sensor was rinsed with HEPES buffer at 150 μL/min until the baseline was stable, typically after 5 min. In Figure S2, MC gave a large frequency drop, indicating adsorption of MC onto CNC surfaces. This shift in frequency is similar to that observed for other adsorbing polysaccharides.1
Figure S2. Normalized frequency (Δf3/3) versus time for QCM-D study of CNCs-coated QCM sensors exposed to MC (1 g/L in 150 mM HEPES buffer). Malvern Mastersizer. The stability of emulsions stabilized with polymers at 0.2 wt. % was investigated by monitoring the emulsion droplet mean diameter change over six days using a Malvern Mastersizer instrument. DEX emulsions displayed extensive coalescence in less than 2 days after being prepared, whereas both HEC and MC showed slow coalescence with MC emulsion being more stable. The emulsion droplet diameter increased by about 270% and 390% for MC emulsion and HEC emulsion, respectively.
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Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals
Figure S3. Mean droplet diameter of 1:1 dodecane-water emulsion stabilized by 0.2 wt. % polymer alone over 150 hours, as measured by Malvern Mastersizer. The mean droplet diameter was taken to be the volume mean diameter (D4/3) from 3 replicate measurements.
Emulsion Stability.
Figure S4. Appearance of emulsions stabilized by CNCs, polymers, or CNCs with polymers after 1 day and 30 days. S3
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Fluorescent Labelling and Localization of Emulsion Components.
Figure S5. UV-vis absorbance spectrum of CNCs-Nile Blue, HEC-DTAF, and MC-DTAF.
Figure S6. Confocal laser scanning micrographs of 1:1 dodecane-water emulsion showing droplets stabilized by CNCs labeled with Nile Blue (appears red) and polymers labeled with DTAF (appears green). Top: CNC-HEC emulsion; bottom: CNC-MC emulsion. All scale bars are 5 µm. S4
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Temperature Stability of Emulsion Droplet Size.
Figure S7. CLSM images of CNC-HEC+MC emulsion at a) 25 °C (before any heating and cooling) and b) 70 °C (after 5 cycles of heating and cooling) (CNCs: 0.15 wt. %, HEC: 0.1 wt. %, MC: 1 wt. %, 25 vol % o/w emulsion). The internal oil phase is stained with Nile Red (appears green). All scale bars are 20 µm.
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Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Effect of Adding Polymer after CNC Pickering Emulsions are Formed.
Figure S8. CLSM images and physical appearance of CNC emulsion (top), CNC emulsion with added HEC (middle, CNC+HEC), and CNC emulsion with added MC (bottom, CNC+MC). For each emulsion sample, both high and low magnification CLSM images are shown (scale bars on left are 100 µm and scale bars on right are 20 µm). The internal oil phase is stained with Nile Red (appears green). When HEC or MC is added to emulsion stabilized with only CNCs, instant emulsion coalescence and breaking is observed. References: (1)
Hu, Z.; Cranston, E. D.; Ng, R.; Pelton, R. Tuning Cellulose Nanocrystal Gelation with Polysaccharides and Surfactants. Langmuir 2014, 30 (10), 2684-2692.
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Synergistic Stabilization of Emulsions and Emulsion Gels with Water-Soluble Polymers and Cellulose Nanocrystals Zhen Hu, Tyler Patten, Robert Pelton, and Emily D. Cranston * Department of Chemical Engineering, McMaster University 1280 Main St. West, Hamilton, Ontario Canada L8S 4L7 * E-mail: [email protected] Number of pages: 6; number of figures: 8 Transmission Electron Microscopy (TEM). The anionic functional groups on CNC particles were selectively stained by mixing a 0.05 mL aliquot of the CNC (0.5 wt. %) with 0.5 mL of a 1 mM uranyl acetate solution and votexing the mixture for 2 min. A single drop of the stained suspension was dropped on a Formvar-coated copper TEM grid and dried for 4 h. TEM images were acquired using a JEOL 1200 EX TEMSCAN microscope operating at 80 kV.
Figure S1. TEM image of sulfated cellulose nanocrystals (CNCs). TEM image of CNCs is presented in Figure S1 and shows well-dispersed rod-shaped nanoparticles with average crystal dimensions of 128 × 7 nm. The average dimensions of these CNCs were determined by measuring the sizes of 100 individual nanocrystals.
S1
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). CNC-coated sensors were prepared using an approach that has been previously used in a similar work. 1 Methyl cellulose (MC) adsorption on CNC surface was measured with an E4 QCM-D instrument from Q-Sense AB (Sweden) where the third, fifth, and seventh overtones were recorded. An aqueous solution of HEPES buffer was injected at a constant flow rate of 150 μL/min until the baseline frequency shift was less than 0.5 Hz over 10 min. Then 1 g/L MC in HEPES buffer was injected at 150 μL/min until the baseline was again stable, typically after 60 min. The sensor was rinsed with HEPES buffer at 150 μL/min until the baseline was stable, typically after 5 min. In Figure S2, MC gave a large frequency drop, indicating adsorption of MC onto CNC surfaces. This shift in frequency is similar to that observed for other adsorbing polysaccharides.1
Figure S2. Normalized frequency (Δf3/3) versus time for QCM-D study of CNCs-coated QCM sensors exposed to MC (1 g/L in 150 mM HEPES buffer). Malvern Mastersizer. The stability of emulsions stabilized with polymers at 0.2 wt. % was investigated by monitoring the emulsion droplet mean diameter change over six days using a Malvern Mastersizer instrument. DEX emulsions displayed extensive coalescence in less than 2 days after being prepared, whereas both HEC and MC showed slow coalescence with MC emulsion being more stable. The emulsion droplet diameter increased by about 270% and 390% for MC emulsion and HEC emulsion, respectively.
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Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals
Figure S3. Mean droplet diameter of 1:1 dodecane-water emulsion stabilized by 0.2 wt. % polymer alone over 150 hours, as measured by Malvern Mastersizer. The mean droplet diameter was taken to be the volume mean diameter (D4/3) from 3 replicate measurements.
Emulsion Stability.
Figure S4. Appearance of emulsions stabilized by CNCs, polymers, or CNCs with polymers after 1 day and 30 days. S3
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Fluorescent Labelling and Localization of Emulsion Components.
Figure S5. UV-vis absorbance spectrum of CNCs-Nile Blue, HEC-DTAF, and MC-DTAF.
Figure S6. Confocal laser scanning micrographs of 1:1 dodecane-water emulsion showing droplets stabilized by CNCs labeled with Nile Blue (appears red) and polymers labeled with DTAF (appears green). Top: CNC-HEC emulsion; bottom: CNC-MC emulsion. All scale bars are 5 µm. S4
Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Temperature Stability of Emulsion Droplet Size.
Figure S7. CLSM images of CNC-HEC+MC emulsion at a) 25 °C (before any heating and cooling) and b) 70 °C (after 5 cycles of heating and cooling) (CNCs: 0.15 wt. %, HEC: 0.1 wt. %, MC: 1 wt. %, 25 vol % o/w emulsion). The internal oil phase is stained with Nile Red (appears green). All scale bars are 20 µm.
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Supporting Information - Synergistic Stabilization of Emulsions and Emulsion Gels with WaterSoluble Polymers and Cellulose Nanocrystals Effect of Adding Polymer after CNC Pickering Emulsions are Formed.
Figure S8. CLSM images and physical appearance of CNC emulsion (top), CNC emulsion with added HEC (middle, CNC+HEC), and CNC emulsion with added MC (bottom, CNC+MC). For each emulsion sample, both high and low magnification CLSM images are shown (scale bars on left are 100 µm and scale bars on right are 20 µm). The internal oil phase is stained with Nile Red (appears green). When HEC or MC is added to emulsion stabilized with only CNCs, instant emulsion coalescence and breaking is observed. References: (1)
Hu, Z.; Cranston, E. D.; Ng, R.; Pelton, R. Tuning Cellulose Nanocrystal Gelation with Polysaccharides and Surfactants. Langmuir 2014, 30 (10), 2684-2692.
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