Fig. 1

SEM（A）and TEM（B）images of alumina nanoparticles"

Fig. 2

Zeta potential of 0.1% alumina nanoparticles dispersed in pure water as a function of pH at 25 ℃"

Fig. 3

Digital photographs（A）and selected micrographs（B）of n-decane-in-water emulsions stabilized by mixtures of 0.5% nano-Al2O3 and CTAB of different concentrations, as well as selected micrographs（C）of n-decane-in-water emulsions stabilized by CTAB alone at different concentrations, taken 24 h（B and C）and 1 month（A）after preparation. CTAB concentration（mmol/L）is given on each vessel and image"

Fig. 4

Digital photographs（A）and selected micrographs（B）of n-decane-in-water emulsions stabilized by 0.01 mmol/L CTAB in combination with alumina nanoparticles at different concentrations（given on each vessel and micrograph in %）, taken 1 week（A）and 24 h（B）after preparation"

Fig. 5

Correlation between the nano-Al2O3 concentration and the CTAB concentration required for stabilizing n-decane-in-water emulsions（a）at 25 ℃, and average droplet diameter of emulsions co-stabilized by nano-Al2O3 and CTAB and stabilized by CTAB alone as a function of CTAB concentration（b）; the average droplet diameter was measured from micrographs of the emulsions"

Fig. 6

SEM images（A）and optical micrographs（B）of dried n-hexane-in-water novel emulsion droplets co-stabilized by 0.5% nano-Al2O3 plus 0.1 mmol/L CTAB（A-1, B） or by 0.06% nano-Al2O3 plus 0.03 mmol/L CTAB（A-2）, and optical micrographs（C） of n-hexane-in-water Pickering emulsion droplets half dried（C-1）and fully dried（C-2）co-stabilized by 0.5% nano-Al2O3 plus 0.1 mmol/L SDS"

Fig. 7

Digital photographs of n-decane-in-water emulsions stabilized by（A）0.5% nano-SiO2 alone,（B）SDS alone at different concentrations and（C） mixture of 0.5% nano-SiO2 and SDS at different concentrations, as well as micrographs of emulsions stabilized by SDS alone（a-c）and by nano-SiO2 in combination with SDS（d-f）, taken 24 h after preparation. SDS concentration（mmol/L）is given on each vessel and image（cmc = 8 mmol/L）"

Fig. 8

Digital photographs of toluene-in-water emulsions stabilized by（A）0.5% nano-Al2O3 alone,（B）CTAB alone at different concentrations and（C）mixtures of 0.5% nano-Al2O3 and CTAB at different concentrations, as well as micrographs of emulsions stabilized by CTAB alone（a-c）and by nano-Al2O3 in combination with CTAB（d-f）, taken 24 h after preparation. CTAB concentration（mmol/L）is given on each vessel and image（cmc=0.9 mmol/L）"

Fig. 9

Digital photographs of tricaprylin-in-water emulsions stabilized by（A）0.5% nano-Al2O3 alone,（B）CTAB alone at different concentrations and（C）mixtures of 0.5% nano-Al2O3 and CTAB at different concentrations, as well as micrographs of emulsions stabilized by CTAB alone（a, b）and by nano-Al2O3 in combination with CTAB（c, d）, taken 24 h after preparation. CTAB concentration（mmol/L）is given on each vessel and image（cmc=0.9 mmol/L）"

Fig. 10

Interfacial tension between n-decane and CTAB aqueous solutions with and without 0.5% nano-Al2O3, as well as the average O/W emulsion droplet size as a function of surfactant concentration at 25 °C"

Fig. 11

Lifetime of n-decane droplets at the pre-equilibrated n-decane/CTAB aqueous solution interface（planar）with and without 0.5% nano-Al2O3 dispersed in the aqueous solution as a function of surfactant concentration at 25 ℃"

Fig. 12

Zeta potential of 0.1% nano-Al2O3 dispersed in aqueous CTAB or SDS solutions as a function of surfactant concentration at 25 ℃"

Fig. 13

Schematic diagram of the stabilization mechanism of the novel emulsions"

Fig. 14

Appearance of n-decane-in-water emulsions stabilized by 0.1% nano-Al2O3 in combination with 0.01 mmol/L CTAB upon addition of Na3PO4, taken 24 h after operation（20-25 ℃）. Na3PO4 concentration（mol/L）in aqueous phase is given"