• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.129-133
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• 1998

We have studied a relationship between the pattern of complex modulus change versus internal phase volume ratio and the rheological consistency of concentrated W/O emulsions with Magnesium Sulfate in the range 0.0 to 0.5 wt% and with different oil polarities, respectively. The rheological consistency with time of concentrated W/O emulsion was checked using Fudoh Rheometer and the coalescence of deformed water droplets was examined using polarized light microscope(LEICA DMRP). To find the pattern of complex modulus change of the concentrated emulsions versus internal phase volume ratio, the effect of varying water phase volume fraction from 0.78 up to 0.85 on viscoelastic measurements was investigated using rotational rheometer (HAAKE Rheostress RS 50). The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. And the pattern of complex modulus increase versus volume ratio has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.167-173
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• 1996

The stability of gel structured emulsion and the effect of polyols on it have been studied by rheological property and interfacial tension. In this paper, three types of gel structured emulsions were prepared by using three polyols respectively(glycerine for sample 1, 1.3 BG for sample 2, PG for sample 3). And both complex modulus($G^*$) and loss angle[$\delta$ = tan-1(G"/G')] of samples were investigated against oscillating shear stress and frequency($\omega$). The results show sample 1 is most highly consistent with oscillating shear stress. And the results were compared with those of accelerated tests concerning storage stability of gel structured emulsion. To correlate consistency of rheological property with storage stability, interfacial tension from which adsorption efficiency of surfactant(Octyldodecyl Ether) could be known was measured. Sample 1 showed the largest value of [$d{\gamma}/dIn_{Cconc. of surfactant}$] in Gibbs equation. In summary, the prediction of stability could be correctly made by the consistency of rheological property(G*,$\gamma$) of gel structured emulsion against oscillating shear stress and it could be supported by measuring interfacial tension. And polyol affected the value of [$d{\gamma}/dIn_{Cconc. of surfactant}$], consequently affected the stability.lity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.108-126
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• 1993

The functions of polyoxyethylene tocopheryl ethers [POE(n)TEs] in emulsion, solubilization and gel were studied. For emulsification of liquid paraffin, POE(10)TE showed better emulsifying effect in O/W emulsions than others tested. The effects of oil and polyol content on the formulation of W/O and O/W emulsions were also studied. In O/W emulsion, the viscosity was increased by increasing the liquid paraffin content, at about 70%, and slightly increased by increasing the propylene glycol content, However, in W/O emulsion, the viscosity was decreased by increasing the oil content, and also decreased by increasing the propylene glycol content, For solubilization of perfume oil, POE(18)TE showed better solubilizing effect than the others tested. The gelling effect of POE(n)TEs increased with ethylene oxide chain length up to 50 moles. The gelling property was evaluated for hardness and viscosity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.139-148
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• 2000

The osmotic pressure is a one of the most important factor affecting stabilization of multiple emulsion in a law hours after experiment. To understand and decrease osmotic pressure between Wl phase and W2 phase, a kinds of humectants were introduced in outer water phase. As a result, Betaine and Glucose had an excellent effect reducing osmotic pressure and NaCl made W/O/W emulsion more stable than MgSO4 did when introduced in inner water phase.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.1
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• pp.1-7
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• 2019

We introduce to prepare liquid crystalline emulsion composed of cetearyl alcohol, cetyl palmitate, sorbitan palmitate, sorbitan olivate, ceramide and so on which can enforce interface between oil-based particle and water phase. In terms of structural analysis, the stability of the liquid crystalline emulsion including ceramide, which is immisible ingredient, at high temperature was proved by polarized microscope, cryo-SEM, small-angle x-ray scattering, in addition to viscometer and static light scattering by physical analysis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.1
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• pp.137-155
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• 1999

The o/w emulsions were prepared by lysolecithin as a biosurfactantsto to emulsify oils with squalane(SQ), liquid paraffin(LP), octylpalmitate(OP), octylstearate(OS), alkyl benzoate(AB), isostearyl benzoate(ISB). The droplets size and shape of o/w emulsions were investigated by laser light scattering, With dynamic light scattering hydrodynamic radius(Rh) of emulsion droplets was varied from 150m to 250m and critical concentration of oil In which the hydrodynamic radius(Rh) of emulsion droplets decreased and increased was found in the point of 0.5wt% oil concentration, and it was found increasing the polarity of oil deccreased the droplets, the droplets size of SQ(polar oil) were lower than SQ(nonpolar oil) With static light scattering radius of gyration(R$_{g}$) of emulusion droplets was to be calculated. From measurements of the ratio of R$_{g}$R$_{h}$ it was found that the shape of droplet of ISB, AB(polar oils) were sphere, for OP, OS(apolar oil) were oblate, for LP, SQ(nonpolar oil) were rod. The viscosity of emulsion in the form of rod was higher than that of emulsion in the form of sphere.e.e.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.11 no.1
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• pp.21-31
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• 1985

The effect of dispersed phase on the stability of emulsion system with polyoxyethylene dodecyl ethers and their variation of ethylene oxide moles was studied by such methods as interfacial tension measurement, centrifugation and droplet size variation with time. The experiments showed that, in interfacial tension measurement, long chain alkanols into dispersed phaes are more effectively adsorbed onto interface, while long chain alkanes nearly not, and in centrifugation, dispersed phase with alkanols is less separated than that with alkanes. On the other hand, alkanes help more stabilyzing emulsion than alkanols in droplet size variation. And the addition of NaCl or Urea, and variation of E.O. moles have very slight effects on the stability with alkanes than with alkanols. Moreover, the longer carbon chain length is, dispersed phase is more effective on emulsion stability. Supposed from these facts is that more stable emulsion can be made with alkanes which retard molecular diffusion by water solubility decrease rather than alkanols which raise resistance to coalescence by rigid interfacial mixed monolayers formation. In conclusion, the stabilities of these emulsions are proved to be more influenced by molecular diffusion than coalescence.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.1
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• pp.19-37
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• 1995

A fine oil -in-water (O/W) emulsion using non-aqueous emulsification technique was developed. And the behaviors of POE(25)octyldodecyl ether in non-aqueous polyol/oil systems were studied by observing the surface tension, interfacial tension, turbidity and transition temperature. It was found that POE(25)octyldodecy1 ether hardly existed as the micelle in the non-aqueous polyol system while, in water, it formed micelles very easily. So, when a polyol, like glycerine in which POE(25)octyldodecyl ether has a poor solubility, was added, POE(25)octyldodecyl ether moved to the surface. After saturated at surface, POE(25)octyldodecyl ether began to precitate. The mean particle size of the final emulsion was 230nm. Also, the emulsion system was stable at 0$^{\circ}C$, 25$^{\circ}C$, 40$^{\circ}C$, 50 $^{\circ}C$ and freeze-thaw cycle chamber for a month, while a conventional emulsion system was unstable. It is concluded that, by pertinent combination of polyols, we can improve the adsorption efficiency of surfactant.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.65-74
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• 1999

We have studied the stability of W/O high internal phase emulsions(HIPE) containing water, cetyl dimethicone copolyol and oils varying magnesium sulfate in the range 0 to 0.5 wt% and oil polarities, respectively. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The greater the increase of complex modulus was, the less coalescence occurred and the more consistent the concentrated emulsions were. The increasing pattern of complex modulus versus volume fraction has been explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsion. The stability is dependent on: (i) the choice of the oil is important, the requirements coincide with the requirements for the formation of the rigid liquid crystalline phases; and (ii) addition of salts the aqueous phase opposes the instability due to coalescence. Increasing the salt concentration increases the refractive index of the aqueous phase. It lowers the difference in the refractive index between the oil and aqueous phases. This decreases the attraction between the water domains, thus increasing the stability.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.440-445
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• 2018

In this study, the stability of O/W cosmetic facial cream emulsions according to HLB values was evaluated by mixing nonionic surfactants, such as Brij 78&72 and Brij 98&92. Brij 78&72 (steareth-20&steareth-2, EMS-01), saturated fatty acid, and Brij 98&92 (oleth-20&oleth-2, EMS-02), unsaturated fatty acid, were used as mixed surfactants. The stability of the O/W emulsion was evaluated by using the emulsion viscosity, particle size, particle size distribution, and zeta-potential. The viscosity of the emulsion increased with the increase of time for EMS-01 while that of EMS-02 decreased with the increase of HLB value. The particle size of both EMS-01 and EMS-02 increased with time. The emulsifier with a HLB value of 10.8, which is the most similar to the required HLB value of mineral oil, 10.5, had the smallest particle size and highest density and also showed the highest emulsion stability. The zeta-potential of both emulsions tended to increase with the HLB value. No significant changes were observed in emulsions of the HLB value of 10.8 or more. The saturated fatty acid system, EMS-01, exhibited a higher zeta-potential value than that of the unsaturated fatty acid EMS-02 and also was superior in the stability.