TY - JOUR
T1 - Phase behaviour and droplet size of oil-in-water Pickering emulsions stabilised with plant-derived nanocellulosic materials
AU - Gestranius, Marie
AU - Stenius, Per
AU - Kontturi, Eero
AU - Sjöblom, Johan
AU - Tammelin, Tekla
N1 - Funding Information:
The Forest Meets Chemistry program by VTT and Aalto University is kindly acknowledged for financing the research. Dr Geir Sørland (Anvent Teknologi AS) is kindly acknowledged for assistance with the NMR measurements. Panu Lahtinen, Katja Pettersson and Ulla Salonen (VTT) are kindly thanked for providing CNF samples and assistance with microscopy. May Saetran and Camilla Dagsgård (NTNU) are kindly acknowledged for excellent laboratory assistance. Reeta Salminen and Dr Benjamin Wilson, (Aalto University) are kindly acknowledged for AFM images and assistance.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2017/4/20
Y1 - 2017/4/20
N2 - The preparation, stability and phase behaviour of
oil-in-water emulsions formed by dodecane and water and
stabilised by naturally amphiphilic, chemically
unmodified cellulose nanofibrils (CNF), TEMPO-oxidized
cellulose nanofibrils (T-CNF) and cellulose nanocrystals
(CNC) were investigated. The stability towards prolonged
storage, high temperature (maximum 85. °C), shear and
dilution with water was evaluated. Droplet size
distributions were determined from micrographs and by NMR
diffusion measurements. Oil-in-water Pickering emulsions
were formed at all stabiliser and O/W ratios (20-35% oil,
0.1-1.5% nanocellulose) for all three nanocellulosic
materials, without the use of any additives. All
emulsions creamed rapidly; the creaming layers remained
stable for at least one month. The volume of creaming
layers formed by CNF and T-CNF are larger and the
stability towards coalescence, low shear and high
temperature of CNF and T-CNF are higher than the
corresponding properties of emulsions stabilised with
CNC. This is probably due to the networks formed by the
longer fibrils. T-CNF forms a dilute stable emulsion in
equilibrium with the creaming layer. No emulsion droplets
were visible in the water phases in equilibrium with the
creaming layers formed by emulsions stabilised by CNC or
CNF. The stability of the dilute T-CNF emulsions is
probably due to the ionic charge of the nanofibrils,
which is higher than that of the CNF or CNC. It seems
that nanocellulosic materials primarily act as
stabilisers against coalescence rather than flocculation.
AB - The preparation, stability and phase behaviour of
oil-in-water emulsions formed by dodecane and water and
stabilised by naturally amphiphilic, chemically
unmodified cellulose nanofibrils (CNF), TEMPO-oxidized
cellulose nanofibrils (T-CNF) and cellulose nanocrystals
(CNC) were investigated. The stability towards prolonged
storage, high temperature (maximum 85. °C), shear and
dilution with water was evaluated. Droplet size
distributions were determined from micrographs and by NMR
diffusion measurements. Oil-in-water Pickering emulsions
were formed at all stabiliser and O/W ratios (20-35% oil,
0.1-1.5% nanocellulose) for all three nanocellulosic
materials, without the use of any additives. All
emulsions creamed rapidly; the creaming layers remained
stable for at least one month. The volume of creaming
layers formed by CNF and T-CNF are larger and the
stability towards coalescence, low shear and high
temperature of CNF and T-CNF are higher than the
corresponding properties of emulsions stabilised with
CNC. This is probably due to the networks formed by the
longer fibrils. T-CNF forms a dilute stable emulsion in
equilibrium with the creaming layer. No emulsion droplets
were visible in the water phases in equilibrium with the
creaming layers formed by emulsions stabilised by CNC or
CNF. The stability of the dilute T-CNF emulsions is
probably due to the ionic charge of the nanofibrils,
which is higher than that of the CNF or CNC. It seems
that nanocellulosic materials primarily act as
stabilisers against coalescence rather than flocculation.
KW - cellulose nanocrystal
KW - cellulose nanofibril
KW - oil-in-water emulsion
KW - phase behaviour
KW - pickering emulsion
KW - TEMPO-oxidized cellulose nanofibril
UR - http://www.scopus.com/inward/record.url?scp=84973130073&partnerID=8YFLogxK
U2 - 10.1016/j.colsurfa.2016.04.025
DO - 10.1016/j.colsurfa.2016.04.025
M3 - Article
SN - 0927-7757
VL - 519
SP - 60
EP - 70
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
ER -