Biomaterials, Artificial Cells and Immobilization Biotechnology
ISSN: 1055-7172 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/ianb18
Rheology of Concentrated Perfluorocarbon Emulsions Yong Ni, David H. Klein & Timothy J. Pelura To cite this article: Yong Ni, David H. Klein & Timothy J. Pelura (1992) Rheology of Concentrated Perfluorocarbon Emulsions, Biomaterials, Artificial Cells and Immobilization Biotechnology, 20:2-4, 869-871, DOI: 10.3109/10731199209119733 To link to this article: http://dx.doi.org/10.3109/10731199209119733
Published online: 11 Jul 2009.
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Citing articles: 3 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ianb18 Download by: [Universite Laval]
Date: 24 April 2016, At: 00:55
BIOMAT.,
ART. CELLS & IMMOB. BIOTECH.,
Z O ( 2 - 4 ) , 869-871 ( 1 9 9 2 )
RHEOLOCY OF CONCENTRATED PERFLUOROCARBON EMULSIONS
Downloaded by [Universite Laval] at 00:55 24 April 2016
Yong Ni, David H. Klein and Tmolhy J. Pelun Alliance PtLVmaceutical Corp.. San Diego, California, USA Oil-in-water emulsions conthing perfluomtylbromide (perflubron; PFOB) at up to about 50 vol.% and stabilized with egg yolk pbospbolipid (EYP) have been prepared and their rheology bas been studied. The emulsions are non-Newtonian, and their viscosities are strongly dependent on the volume fnction of pertlubron. as well as on pmcessing and formulation. Using a controlled-stress rbeometer with double-gap geometry, the viscosity at shear rates less h n 0. I sec-1an be measured. Tbe viscoelastic properties of the emulsions have been explored using oscilhtion and stress-sweep techniques and an be used for the prediction of emulsion stability. MatPrbls and Metbods Pertluhn and naturnl egg yolk phospholipid were used as purchased without further purification. Bohlin CS (controlled-suess) rheMneter with C25 (concentric cylinder, 12ml sample) or DG (double gap, 30 ml sample) meauring geometry was used for dynamic (stress-sweep and oscillation) and smtic (viscosity, etc.) measurements. BrooWield d p l a t e viscometer (Iml sample) was also used for routine viscosity measurements. Results and Discussion Viscosiry vs. Concenfraion offeflubron. Concentrated perfluorocarbon (PFC) emulsions are non-Newtonian i viscosities are strongly dependent on the PFC conenuation. Viscosities (viscosity varies with shear mte). W of perflubron emulsions at different concenuations are shown in f i g . 1. The viscosity of the I 10% wlv perflubron
emulsion at shear 0.1sw-' was mensured to be. 9160 cps.
perflubron concenlralion 1; w/v
vd. X
110
57.3
90
46.9
Fig. 1. Viscosity ofperflubm emulsions at 25T. Viscosities for 30-1lXl% w/v at shm I/= 869 Copytight 0 1992 by Marcel Dekker, Inc.
are exvapohted.
Downloaded by [Universite Laval] at 00:55 24 April 2016
070
NI, KLEIN, AND PELURA
5
15 Pressure x
Rg. 2.
109
(3Viscosity and (b)initial diameter @m)vs. P (psig) and Pass Number with T = 45T.
Fig. 3. G/G" vs frequency and tempenlure.
Viscosity vs. Processing. Tbe viscosities of petilubmn emulsions we also dependent on homogenization parameters T (temperature). P (pmsure) and number of passes. neir effecls on initid viscosities of 100% w/v petilubroo mulsioos an illuswed in Fig. 2n. Tbe figure sbows the viscosities (It &ear nte I/sec, extrapolated by log-log fit and then fitted to ECHlP [l] by P quodriuic model. Pmcmsiiog has P h g e influence on the drop size dthe drop deformability of emulsions, and subsequently on the viscosity. For compiuison. Ibe corresponding initial m m median diameters mcasured by Horiba CAPA-700 piuticle size distribution analyzer and fiued by WHIP with a q u a l d c model we sbown in Fig. 2b. DyMmic Rholop. [24] We L v e been interesled in predicting emulsion stability by rbeologid methods. Rotyy viscosity mCiWrCment fthe emulsioo dmps to flow past each otber and does not reflect the response
-
RHEOLOGY OF CONCENTRATED PFC EMULSIONS
Downloaded by [Universite Laval] at 00:55 24 April 2016
s* 1000
Fig. 4. S ()lm3/month) vs. P (psig) and T ("c)with P w = 8.
of the emulsion aging on a shelf. Dynamic oscillatory technique consists of inputting il sinusoidal stress (a) of frequency (0)to an emulsion and musing a stnin (9to iuise with an o u t - o f - p b angle 6. Input stress: a = aoeiux Output stmin: y = y,e'(a-@ or G*=G'+iG". Complex modulus G* is the ratio of stress to wain: G* = a/y= (ady&' with elastic modulus G' = (a,,/yo)Cos6 and viscous modulus G" = (a&Jsinb. (i) Stress Sweep Tea. Oscillatory measurements should be &ed out within the linear viscoelostic region (LVR).Fmt,a stress sweep lest was run to determine the LVR. Within the LVR. both G' and G" rue independent of stnin or stress; they rue functions of temperature and frequency only. (ii) Oscillatory Measurement. Oscillatory frequency sweeps from 0.02 to 5 Hz,were performed at 5, 15.25. 35 and 45% Plotting G'/G"ils a function of frequency and temperature generates a 3-D surface. Fig. 3 is a contour plot by Plot-IT plotling/statistical package [5] of a 100% w/v perflubron emulsion; its T and P rue shown in Fig. 4. (iii) Emulsion Slability. 16) For PFCEYP emulsions we have observed that the drop volume increases linearly with time. the drop gmwth nte is proponiod to cPIRT and increases os PFC concentration (C) increases. Thus we &tine "Stability Pnrameter" S as the slope of linear tit of the cube of mean diameter vs. time. in pn3/month. S is an explicit function of T and C. "Stability Parmeter" S has been used in sWility evaluation for pmcess parameter optimization. The S values at viuious combinations of temperature and pressure were fitted to ECHIP [I] by a quadratic model. An example is illuslmted in Fig.4, which shows the observed stability of 100% w/v (52 vol.%) perfiubron emulsions. Fig. 4 also shows the P and T of one of the emulsions shown in Fig. 3. (iv) Correlation of C / G " with Stability. I t has been reported for empirical correlation of stability of concentrateddispersions with dynamic rheological data that G'/G"ratios and the volume underneath the surfaces conelate well wilb observed sWility pmperties.[4] Studies are currently Wing performed which follow this wmh. References
I. EXPWMENTS IN A CHIP, Copyright 1983-1989, ECHIP, Inc.. Delaware. 2. H. A. Banes el al., An Introduction to Rheology, 1989, Elsevier, Amsterdam. 3.1. D. Few, Viscoelanic Propenies of Polymers. 1980, Wiley and Sons. 4. P. F. Reboa aod M.C. Fryao, Rheological Prediction of the Physical Stability of Concentrated Dispersions Containing Parliculates, April 1990. AOCS National Meeting. Baltimore, MD. 5. Plot-IT, Copyright 1991, Scientific h g n m m i n g Enterprises, Michigan. 6.Y. Ni, T. J. Pelura and D.Song, Dropler Size Stability Parameter of PFC Emulsions, June 1991.65th Colloid and Surface Science Symposium. Oklahoma City. OK.
ISSN: 1055-7172 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/ianb18
Rheology of Concentrated Perfluorocarbon Emulsions Yong Ni, David H. Klein & Timothy J. Pelura To cite this article: Yong Ni, David H. Klein & Timothy J. Pelura (1992) Rheology of Concentrated Perfluorocarbon Emulsions, Biomaterials, Artificial Cells and Immobilization Biotechnology, 20:2-4, 869-871, DOI: 10.3109/10731199209119733 To link to this article: http://dx.doi.org/10.3109/10731199209119733
Published online: 11 Jul 2009.
Submit your article to this journal
Article views: 5
View related articles
Citing articles: 3 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ianb18 Download by: [Universite Laval]
Date: 24 April 2016, At: 00:55
BIOMAT.,
ART. CELLS & IMMOB. BIOTECH.,
Z O ( 2 - 4 ) , 869-871 ( 1 9 9 2 )
RHEOLOCY OF CONCENTRATED PERFLUOROCARBON EMULSIONS
Downloaded by [Universite Laval] at 00:55 24 April 2016
Yong Ni, David H. Klein and Tmolhy J. Pelun Alliance PtLVmaceutical Corp.. San Diego, California, USA Oil-in-water emulsions conthing perfluomtylbromide (perflubron; PFOB) at up to about 50 vol.% and stabilized with egg yolk pbospbolipid (EYP) have been prepared and their rheology bas been studied. The emulsions are non-Newtonian, and their viscosities are strongly dependent on the volume fnction of pertlubron. as well as on pmcessing and formulation. Using a controlled-stress rbeometer with double-gap geometry, the viscosity at shear rates less h n 0. I sec-1an be measured. Tbe viscoelastic properties of the emulsions have been explored using oscilhtion and stress-sweep techniques and an be used for the prediction of emulsion stability. MatPrbls and Metbods Pertluhn and naturnl egg yolk phospholipid were used as purchased without further purification. Bohlin CS (controlled-suess) rheMneter with C25 (concentric cylinder, 12ml sample) or DG (double gap, 30 ml sample) meauring geometry was used for dynamic (stress-sweep and oscillation) and smtic (viscosity, etc.) measurements. BrooWield d p l a t e viscometer (Iml sample) was also used for routine viscosity measurements. Results and Discussion Viscosiry vs. Concenfraion offeflubron. Concentrated perfluorocarbon (PFC) emulsions are non-Newtonian i viscosities are strongly dependent on the PFC conenuation. Viscosities (viscosity varies with shear mte). W of perflubron emulsions at different concenuations are shown in f i g . 1. The viscosity of the I 10% wlv perflubron
emulsion at shear 0.1sw-' was mensured to be. 9160 cps.
perflubron concenlralion 1; w/v
vd. X
110
57.3
90
46.9
Fig. 1. Viscosity ofperflubm emulsions at 25T. Viscosities for 30-1lXl% w/v at shm I/= 869 Copytight 0 1992 by Marcel Dekker, Inc.
are exvapohted.
Downloaded by [Universite Laval] at 00:55 24 April 2016
070
NI, KLEIN, AND PELURA
5
15 Pressure x
Rg. 2.
109
(3Viscosity and (b)initial diameter @m)vs. P (psig) and Pass Number with T = 45T.
Fig. 3. G/G" vs frequency and tempenlure.
Viscosity vs. Processing. Tbe viscosities of petilubmn emulsions we also dependent on homogenization parameters T (temperature). P (pmsure) and number of passes. neir effecls on initid viscosities of 100% w/v petilubroo mulsioos an illuswed in Fig. 2n. Tbe figure sbows the viscosities (It &ear nte I/sec, extrapolated by log-log fit and then fitted to ECHlP [l] by P quodriuic model. Pmcmsiiog has P h g e influence on the drop size dthe drop deformability of emulsions, and subsequently on the viscosity. For compiuison. Ibe corresponding initial m m median diameters mcasured by Horiba CAPA-700 piuticle size distribution analyzer and fiued by WHIP with a q u a l d c model we sbown in Fig. 2b. DyMmic Rholop. [24] We L v e been interesled in predicting emulsion stability by rbeologid methods. Rotyy viscosity mCiWrCment fthe emulsioo dmps to flow past each otber and does not reflect the response
-
RHEOLOGY OF CONCENTRATED PFC EMULSIONS
Downloaded by [Universite Laval] at 00:55 24 April 2016
s* 1000
Fig. 4. S ()lm3/month) vs. P (psig) and T ("c)with P w = 8.
of the emulsion aging on a shelf. Dynamic oscillatory technique consists of inputting il sinusoidal stress (a) of frequency (0)to an emulsion and musing a stnin (9to iuise with an o u t - o f - p b angle 6. Input stress: a = aoeiux Output stmin: y = y,e'(a-@ or G*=G'+iG". Complex modulus G* is the ratio of stress to wain: G* = a/y= (ady&' with elastic modulus G' = (a,,/yo)Cos6 and viscous modulus G" = (a&Jsinb. (i) Stress Sweep Tea. Oscillatory measurements should be &ed out within the linear viscoelostic region (LVR).Fmt,a stress sweep lest was run to determine the LVR. Within the LVR. both G' and G" rue independent of stnin or stress; they rue functions of temperature and frequency only. (ii) Oscillatory Measurement. Oscillatory frequency sweeps from 0.02 to 5 Hz,were performed at 5, 15.25. 35 and 45% Plotting G'/G"ils a function of frequency and temperature generates a 3-D surface. Fig. 3 is a contour plot by Plot-IT plotling/statistical package [5] of a 100% w/v perflubron emulsion; its T and P rue shown in Fig. 4. (iii) Emulsion Slability. 16) For PFCEYP emulsions we have observed that the drop volume increases linearly with time. the drop gmwth nte is proponiod to cPIRT and increases os PFC concentration (C) increases. Thus we &tine "Stability Pnrameter" S as the slope of linear tit of the cube of mean diameter vs. time. in pn3/month. S is an explicit function of T and C. "Stability Parmeter" S has been used in sWility evaluation for pmcess parameter optimization. The S values at viuious combinations of temperature and pressure were fitted to ECHIP [I] by a quadratic model. An example is illuslmted in Fig.4, which shows the observed stability of 100% w/v (52 vol.%) perfiubron emulsions. Fig. 4 also shows the P and T of one of the emulsions shown in Fig. 3. (iv) Correlation of C / G " with Stability. I t has been reported for empirical correlation of stability of concentrateddispersions with dynamic rheological data that G'/G"ratios and the volume underneath the surfaces conelate well wilb observed sWility pmperties.[4] Studies are currently Wing performed which follow this wmh. References
I. EXPWMENTS IN A CHIP, Copyright 1983-1989, ECHIP, Inc.. Delaware. 2. H. A. Banes el al., An Introduction to Rheology, 1989, Elsevier, Amsterdam. 3.1. D. Few, Viscoelanic Propenies of Polymers. 1980, Wiley and Sons. 4. P. F. Reboa aod M.C. Fryao, Rheological Prediction of the Physical Stability of Concentrated Dispersions Containing Parliculates, April 1990. AOCS National Meeting. Baltimore, MD. 5. Plot-IT, Copyright 1991, Scientific h g n m m i n g Enterprises, Michigan. 6.Y. Ni, T. J. Pelura and D.Song, Dropler Size Stability Parameter of PFC Emulsions, June 1991.65th Colloid and Surface Science Symposium. Oklahoma City. OK.
