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Rotational brownian movement of poly(tetrafluoroethylene) colloids as studied by the conductance stopped-flow technique
Rotational Brownian Movement of Poly(tetrafluoroethylene) Colloids as Studied by the Conductance Stopped-Flow Technique
The rotational relaxation time and rotational diffusion coefficient (Dr) for ellipsoidal colloids of poly(tetrafluoroethylene) in aqueous suspension are determined conveniently and precisely by the conductanee stopped-flow technique. The Dr values observed ( 13-21 s -l ) are smaller than those calculated by Perrin's equation (80 s-~). The deviation can be explained by the significant contribution of the Debye-Hiickel double-layer thickness (Debye screening length) in the absence of foreign salt. © 1990 AcademicPress,Inc.
INTRODUCTION In previous papers (1-4), one of the authors used the conductance stopped-flow (CSF), spectrophotometric stopped-flow, and birefringence stopped-flow techniques, for the first time, to obtain information on the rotational relaxation time (T) and rotational diffusion coefficient (Dr) of anisotropic colloid particles of tungstic acid and lineartype macroions such as sodium poly(styrene sulfonate) and sodium salt of deoxyribonucleic acid (DNA). We report here the rotational Brownian motion of an ellipsoidal colloid of poly (tetrafluoroethylene) (PTFE). Dr of PTFE was determined by the CSF method. In this method two types of solution are mixed in a cell and the solution is then allowed to flow into an observation cell (a narrow tube 2 m m in diameter) under a strong shear rate. The anisotropic molecules are expected to orient themselves along the flow direction during continuous flow. When the solution flow is stopped, the molecules revert to free rotation in a Brownian random distribution. The initial anisotropies of the electrical conductivity, Ko- K+ at t = 0, decrease to zero. This process depends on the dimensions of the molecules and is described by a relaxation function: K - K+ = (Ko - K + ) e x p ( - t / r ) .
[11
r = 1~6Dr,
[2]
Here
where ro is the electrical conductivity at the initial state of orientation, caused by the shear flow in the observation cell. r + denotes the conductivity at a random distribution at t = ~ , while r is the conductance at time t. z is the rotational relaxation time. The translational diffusion is not significant in the stopped-flow method, since the flow
of the solvent molecules stops completely when the observation starts. The CSF method has been applied to the analysis of various fast interionic reactions, i.e., micellar equilibria of ionic detergents (5), macroion complexations with neutral polymers (6), metal ions (7) and oppositely charged macroions (8), enzymatic reactions (9), and other chemical reactions ( 10-17 ). Note that the relaxation processes of the conductance anisotropy were first discussed for ionic detergents (18, 19), polyphosphates (20-23), graphitic acid colloids ( 19, 24 ), DNA (24), and poly ( methacrylic acid) (25). MATERIALS AND METHODS The PTFE particles were prepared by emulsion polymerization of tetrafluoroethylene at 70°C (26). Ammon i u m p e r f l u o r o o c t a n o a t e and b i s ( f l - c a r b o x y p r o pyl)peroxide were used as an emulsifier and an initiator, respectively. The PTFE colloids we used were mixtures of lozenge (or brick-like ) particles and rod-like ( or lath-like) particles. Most of our sample was lozenge (ellipsoidal; ca. 90%) and with a small number of log rods (ca. 10%). The major (2c), middle (2b), and minor (2a) axes were 320, 160, and 160 n m measured by an electron microscope (27). According to R a t h e t aL (28) the lozenges were formed by successive folding of the rods. Jennings et al. (29-31 ) clarified the high structural nature of anisotropy and crystallinity of the particles. The PTFE particles were carefully purified several times by dialysis and then treated with a mixed bed of cation- and anion-exchange resins [Bio-Rad, AG501-X8(D), 20-50 mesh] for more than 10 days. Water used for the purification and for solution preparations was deionized by using cation- and anionexchange resins (Puric-R, Type G 10, Organo Co., Tokyo) and further purified by a Milli-Q reagent-grade water system (Millipore Co., Bedford, MA).
300 0021-9797/90 $3.00 Copyright© 1990by AcademicPress,Inc. All rightsof reproductionin any formreserved.
Journal of Colloid and Interface Science,
Vol. 135,No. 1, March 1, 1990
NOTES
301
2
FIG. I. Typical traces of relaxation of CSF measurements of PTFE colloids. Curve 1, 0.84 vol%; curve 2, 0.63 vol%. Horizontal full scale = 0.2 s. Arrows show the instant of stopping the flow.
The details of the conductance stopped-flow (CSF) apparatus have been described previously (1, 5, 13). The sample solution from the mixer, which was made of Teflon and was a four-jet type, flowed between platinum plates. The platinum plate electrodes (2 × 10 ram) were fixed on opposite walls (2 m m apart ) inside the observation cell made of epoxy resins. For each run at 25°C, about 0.2 cm 3 of solution was required. A value of 1.30 cm -1 was obtained for the cell constant. An ac current of 50 kHz was applied to the Wicn bridge. The applied voltage across the cell was kept at 2 V (root mean square). The time change of the solution conductance was amplified in two stages and monitored by a memoriscope a n d / o r digital memory and an X - Y recorder after rectification. The dead time was 1 ms. Flow rate was estimated roughly to be 4 ms
equations (32) for ellipsoidal PTFE colloids (Eqs. [ 3 ] [6]) by using the crystallographic size (a = b = 80 nm, c = 160 nm), was 80 s -1.
Dr = [3kT(a2P + b2Q)]/[ 16~-~/(a2 + b2)]
[3]
P= f ds/[(a2 + s)V(a~ + s)(b2 + s)(c~ + s)]
[4]
a2P + b2Q+ c2R
= f d s / V ( a 2 + s)(b 2 + s)(c + s) P+Q+R=2/(abc),
I.
RESULTS AND DISCUSSION Figure 1 shows typical examples of the relaxation curves of the anisotropy in conductance obtained by the CSF measurements. In these experiments the same solution was poured into two vessels and then mixed. From the first-order plot, r was obtained. The concentration dependence o f t values from the CSF method is shown in Fig. 2. The ~- values seem to decrease slightly with PTFE concentration, though the experimental uncertainties are large. This decreasing tendency can be explained by the enlarged effective size of the particle due to the Debye screening length (double-layer thickness). The details of this effect will be discussed later. Dr is obtained directly from the observed r values by using Eq. [2]. The Dr values thus obtained were between 13 and 21 s -1. Dr, which was calculated from Perrin's
[5]
a
[6]
The constants P, Q, and R are derived from Eqs. [ 3 ] to [ 5]. k, T, and n in Eq. [ 3 ] are the Boltzmann constant, 0.015 -
t~
o.olo
0.005
0
-
+
r
r
+++ I 0.5 [PTFEI
+ I 1.0
1.5
(vot%)
FIG. 2. Concentration dependencies of r for PTFE colloids.
Journal of Colloid and Interface Science, Vol. 135, No. 1, March I, 1990
302
NOTES
the absolute temperature, and the viscosity of the solvent, respectively. The observed Dr values were smaller than the calculated values. The inequality was obtained for tungstic acid colloids ( 1). Since the experiments were done in the absence of foreign salt ("salt-free" system), the Debye-Htickel double-layer thickness (D~) should be taken into account in the evaluation of the effective size of the colloids; that is, the effective values of the a, b, and e axes are a + Dl, b + Dl, and c + Dh respectively. DI = (47re2n/~kBT) -'/2,
[7]
where e is the electronic charge, ka is the Boltzmann constant, e is the dielectric constant of the solvent, and n is the concentration of free-state ("diffusible") cations and anions in solution, n corresonds to that of protons. We have no information on the effective charge number on the surface of PTFE colloid. We estimated the number of free H + ions from the solution conductance and from the reference value of equivalent conductance of protons. The evaluated D~ values for our system were about 300 nm. This correction term OfDl is quite significant for the PTFE colloids. Note that the D~ values estimated from Perrin's equation and the observed values of Dr were 150 to 200 nm. The increasing tendency of Dr with concentration is also explained adequately by the decrease in Dt with concentration is also explained adequately by the decrease in Dt with concentration in Eq. [ 7 ]. The significance of the Debye length has often been pointed out for solution properties of various colloids and polyelectrolytes in saltfree systems, such as the ordering of monodisperse colloids (33-35), expanded conformation of ionic flexible polymers (4, 36-38), and low mobility of spherical colloids at extremely low ionic strengths (39-41 ). It should be mentioned here that recently Rehage et al. (42) measured Dr of PTFE particles by the electrooptic and rheological techniques. They found that the Dr values showed no colloid concentration dependencies and agreed with the calculated values theoretically by using the crystallographic sizes of the particles. The apparent different conclusions on the relationship between observed Dr values and their theoretical values is explained reasonably by the difference in the experimental conditions; i.e., the ionic concentrations of suspensions of Rehage et al. were rather high whereas our samples were deionized completely by the ion-exchange resins.
REFERENCES 1. Okubo, T., J. Amer. Chem. Soc. 109, 1913 (1987). 2. Okubo, T., J. Phys. Chem. 91, 1977 (1987). 3. Okubo, T., J. Chem. Soc. Faraday Trans. i 84, 703 (1988). Journalof ColloidandInterfaceScience,Vol. 135,No. 1, March1, 1990
4. Okubo, T., Macromolecules, 22, 1818 (1989). 5. Okubo, T., Kitano, H., Ishiwatari, T., and Ise, N., Proc. R. Soc. London Ser. A 366, 81 (1979). 6. Okubo, T., Biophys. Chem. 111, 425 (1980). 7. Okubo, T., and Enokida, A., J. Chem. Soc. Faraday Trans. 1 79, 1639 (1983). 8. Okubo, T., Hongyo, K., and Enokida, A., J. Chem. Soc. Faraday Trans. 1 80, 2087 (1984). 9. Kitano, H., Hasegawa, J., Iwai, S., and Okubo, T., Polym. Bull. (Berlin) 16, 89 (1986). 10. Okubo, T., and Ise, N., Polym. Bull. (Berlin) 1, 109 (1978). 11. Sawamoto, M., Higashimura, T., Enokida, A., and Okubo, T., Polym. Bull. (Berlin) 16, 89 (1986). 12. Okubo, T., "Dynamic Aspects of Polyelectrolytes and Biomembranes" (F. Oosawa, Ed.), p. 111. Kodansha, Tokyo, 1982. 13. Okubo, T., MakromoL Chem. SuppL 14, 161 (1985). 14. Kitano, H., Hasegawa, J., Iwai, S., and Okubo, T., J. Phys. Chem. 90, 6281 (1986). 15. Okubo, T., J. Chem. Soc. Faraday Trans. 1 84, 3567 (1988). 16. Okubo, T., Kitano, H., and lwai, S., J. Chem. Soc. Faraday Trans. 1 84, 4317 (1988). 17. Okubo, T., Maeda, Y., and Kitano, H., J. Phys. Chem., 93, 372 (1989). 18. Heckmann, K., Z. Phys. Chem., N. F. 9, 318 (1959). 19. G/Stz, K. G., and Heckmann, K., J, Colloid Sci. 13, 266 (1958). 20. Schindewolf, U., Z. Elektrochem. 58, 697 (1954). 21. Eigen, M., and Schwarz, G., J. Colloid Sci. 12, 181 (1957). 22. Schwarz, G., Z. Phys. Chem., N. F. 19, 286 (1959). 23. Heckmann, K., and G6tz, K. G., Z. Elektrochem. 62, 281 (1958). 24. GiStz, K. G., Z ColloidSci. 20, 289 (1965). 25. Kern, E. E., and Anderson, D. K., J, Polym. Sci. Part A1 6, 2765 (1968). 26. Ottewill, R. H., and Rance, D. G., Croat. Chim. Acta 50, 65 (1977). 27. Okubo, T. and Aotani, S., Colloid Polym. Sci. 266, 1049 (1988). 28. Rath, E. J., Evanco, M. A., Fredericks, R. J., and Reimschuessel, P. C., J. Polym. Sci. Part A2 10, 1337 (1972). 29. Jennings, B. R., and Oaldey, D. M., AppL Opt. 21, 1519 (1982). 30. Oakley, D. M., Jennings, B. R., Waterman, D. R., and Fairey, R. C., J. Phys. E 15, 1077 (1982). 31. Jennings, B. R., and Ridler, P. J., Proc. R. Soc. London Ser. A 411, 225 (1987). 32. Perrin, F., J. Phys. Radium. 5, 497 (1934). 33. Hachisu, S., and Kobayashi, Y., J. Colloid Interface Sci. 46, 470 (1974).
NOTES 34. Pieranski, P., Contemp. Phys. 24, 25 (1983). 35. Okubo, T., Accounts Chem. Res. 21, 281 (1988). 36. Barenes, C. J., Chan, D. Y. C., Everett, D. H., and Yates, D. E., J. Chem. Soc. Faraday Trans. 2 74, 136 (1978). 37. Giordano, R., Maisano, G., Mallamace, F., Micali, N., and Wanderlingh, F., J. Chem. Phys. 75, 4770 (1981). 38. Drifford, M., and Dalbiez, P., J. Phys. Chem. 88, 5368 (1984). 39. Shaw, J. N., and Ottewill, R. H., Nature (London) 208, 681 (1984). 40. Goff, J. R., and Luner, P., J. Colloid Interface Sci. 99, 468 (1984). 4i. Okubo, T., at. Phys. Chem., 93, 4352 (1989). 42. Angel, M., Hoffmann, H., Huber, G., and Rehage, H., Bet. Bunsenges. Phys. Chem. 92, 10 (1988).
303 TSUNEO OKUBO 1
Department of Polymer Chemistry Kyoto University Kyoto 606, Kyoto, Japan TETSUOSHIMIZU R & D Department Daikin Industries, Ltd. Settsu 566, Osaka, Japan Received March 28, 1989; accepted June 5, 1989
To whom correspondence and reprint requests should be addressed.
JournalofColloidandInterfaceScience,Vol.135,No. 1, March1, 1990
The rotational relaxation time and rotational diffusion coefficient (Dr) for ellipsoidal colloids of poly(tetrafluoroethylene) in aqueous suspension are determined conveniently and precisely by the conductanee stopped-flow technique. The Dr values observed ( 13-21 s -l ) are smaller than those calculated by Perrin's equation (80 s-~). The deviation can be explained by the significant contribution of the Debye-Hiickel double-layer thickness (Debye screening length) in the absence of foreign salt. © 1990 AcademicPress,Inc.
INTRODUCTION In previous papers (1-4), one of the authors used the conductance stopped-flow (CSF), spectrophotometric stopped-flow, and birefringence stopped-flow techniques, for the first time, to obtain information on the rotational relaxation time (T) and rotational diffusion coefficient (Dr) of anisotropic colloid particles of tungstic acid and lineartype macroions such as sodium poly(styrene sulfonate) and sodium salt of deoxyribonucleic acid (DNA). We report here the rotational Brownian motion of an ellipsoidal colloid of poly (tetrafluoroethylene) (PTFE). Dr of PTFE was determined by the CSF method. In this method two types of solution are mixed in a cell and the solution is then allowed to flow into an observation cell (a narrow tube 2 m m in diameter) under a strong shear rate. The anisotropic molecules are expected to orient themselves along the flow direction during continuous flow. When the solution flow is stopped, the molecules revert to free rotation in a Brownian random distribution. The initial anisotropies of the electrical conductivity, Ko- K+ at t = 0, decrease to zero. This process depends on the dimensions of the molecules and is described by a relaxation function: K - K+ = (Ko - K + ) e x p ( - t / r ) .
[11
r = 1~6Dr,
[2]
Here
where ro is the electrical conductivity at the initial state of orientation, caused by the shear flow in the observation cell. r + denotes the conductivity at a random distribution at t = ~ , while r is the conductance at time t. z is the rotational relaxation time. The translational diffusion is not significant in the stopped-flow method, since the flow
of the solvent molecules stops completely when the observation starts. The CSF method has been applied to the analysis of various fast interionic reactions, i.e., micellar equilibria of ionic detergents (5), macroion complexations with neutral polymers (6), metal ions (7) and oppositely charged macroions (8), enzymatic reactions (9), and other chemical reactions ( 10-17 ). Note that the relaxation processes of the conductance anisotropy were first discussed for ionic detergents (18, 19), polyphosphates (20-23), graphitic acid colloids ( 19, 24 ), DNA (24), and poly ( methacrylic acid) (25). MATERIALS AND METHODS The PTFE particles were prepared by emulsion polymerization of tetrafluoroethylene at 70°C (26). Ammon i u m p e r f l u o r o o c t a n o a t e and b i s ( f l - c a r b o x y p r o pyl)peroxide were used as an emulsifier and an initiator, respectively. The PTFE colloids we used were mixtures of lozenge (or brick-like ) particles and rod-like ( or lath-like) particles. Most of our sample was lozenge (ellipsoidal; ca. 90%) and with a small number of log rods (ca. 10%). The major (2c), middle (2b), and minor (2a) axes were 320, 160, and 160 n m measured by an electron microscope (27). According to R a t h e t aL (28) the lozenges were formed by successive folding of the rods. Jennings et al. (29-31 ) clarified the high structural nature of anisotropy and crystallinity of the particles. The PTFE particles were carefully purified several times by dialysis and then treated with a mixed bed of cation- and anion-exchange resins [Bio-Rad, AG501-X8(D), 20-50 mesh] for more than 10 days. Water used for the purification and for solution preparations was deionized by using cation- and anionexchange resins (Puric-R, Type G 10, Organo Co., Tokyo) and further purified by a Milli-Q reagent-grade water system (Millipore Co., Bedford, MA).
300 0021-9797/90 $3.00 Copyright© 1990by AcademicPress,Inc. All rightsof reproductionin any formreserved.
Journal of Colloid and Interface Science,
Vol. 135,No. 1, March 1, 1990
NOTES
301
2
FIG. I. Typical traces of relaxation of CSF measurements of PTFE colloids. Curve 1, 0.84 vol%; curve 2, 0.63 vol%. Horizontal full scale = 0.2 s. Arrows show the instant of stopping the flow.
The details of the conductance stopped-flow (CSF) apparatus have been described previously (1, 5, 13). The sample solution from the mixer, which was made of Teflon and was a four-jet type, flowed between platinum plates. The platinum plate electrodes (2 × 10 ram) were fixed on opposite walls (2 m m apart ) inside the observation cell made of epoxy resins. For each run at 25°C, about 0.2 cm 3 of solution was required. A value of 1.30 cm -1 was obtained for the cell constant. An ac current of 50 kHz was applied to the Wicn bridge. The applied voltage across the cell was kept at 2 V (root mean square). The time change of the solution conductance was amplified in two stages and monitored by a memoriscope a n d / o r digital memory and an X - Y recorder after rectification. The dead time was 1 ms. Flow rate was estimated roughly to be 4 ms
equations (32) for ellipsoidal PTFE colloids (Eqs. [ 3 ] [6]) by using the crystallographic size (a = b = 80 nm, c = 160 nm), was 80 s -1.
Dr = [3kT(a2P + b2Q)]/[ 16~-~/(a2 + b2)]
[3]
P= f ds/[(a2 + s)V(a~ + s)(b2 + s)(c~ + s)]
[4]
a2P + b2Q+ c2R
= f d s / V ( a 2 + s)(b 2 + s)(c + s) P+Q+R=2/(abc),
I.
RESULTS AND DISCUSSION Figure 1 shows typical examples of the relaxation curves of the anisotropy in conductance obtained by the CSF measurements. In these experiments the same solution was poured into two vessels and then mixed. From the first-order plot, r was obtained. The concentration dependence o f t values from the CSF method is shown in Fig. 2. The ~- values seem to decrease slightly with PTFE concentration, though the experimental uncertainties are large. This decreasing tendency can be explained by the enlarged effective size of the particle due to the Debye screening length (double-layer thickness). The details of this effect will be discussed later. Dr is obtained directly from the observed r values by using Eq. [2]. The Dr values thus obtained were between 13 and 21 s -1. Dr, which was calculated from Perrin's
[5]
a
[6]
The constants P, Q, and R are derived from Eqs. [ 3 ] to [ 5]. k, T, and n in Eq. [ 3 ] are the Boltzmann constant, 0.015 -
t~
o.olo
0.005
0
-
+
r
r
+++ I 0.5 [PTFEI
+ I 1.0
1.5
(vot%)
FIG. 2. Concentration dependencies of r for PTFE colloids.
Journal of Colloid and Interface Science, Vol. 135, No. 1, March I, 1990
302
NOTES
the absolute temperature, and the viscosity of the solvent, respectively. The observed Dr values were smaller than the calculated values. The inequality was obtained for tungstic acid colloids ( 1). Since the experiments were done in the absence of foreign salt ("salt-free" system), the Debye-Htickel double-layer thickness (D~) should be taken into account in the evaluation of the effective size of the colloids; that is, the effective values of the a, b, and e axes are a + Dl, b + Dl, and c + Dh respectively. DI = (47re2n/~kBT) -'/2,
[7]
where e is the electronic charge, ka is the Boltzmann constant, e is the dielectric constant of the solvent, and n is the concentration of free-state ("diffusible") cations and anions in solution, n corresonds to that of protons. We have no information on the effective charge number on the surface of PTFE colloid. We estimated the number of free H + ions from the solution conductance and from the reference value of equivalent conductance of protons. The evaluated D~ values for our system were about 300 nm. This correction term OfDl is quite significant for the PTFE colloids. Note that the D~ values estimated from Perrin's equation and the observed values of Dr were 150 to 200 nm. The increasing tendency of Dr with concentration is also explained adequately by the decrease in Dt with concentration is also explained adequately by the decrease in Dt with concentration in Eq. [ 7 ]. The significance of the Debye length has often been pointed out for solution properties of various colloids and polyelectrolytes in saltfree systems, such as the ordering of monodisperse colloids (33-35), expanded conformation of ionic flexible polymers (4, 36-38), and low mobility of spherical colloids at extremely low ionic strengths (39-41 ). It should be mentioned here that recently Rehage et al. (42) measured Dr of PTFE particles by the electrooptic and rheological techniques. They found that the Dr values showed no colloid concentration dependencies and agreed with the calculated values theoretically by using the crystallographic sizes of the particles. The apparent different conclusions on the relationship between observed Dr values and their theoretical values is explained reasonably by the difference in the experimental conditions; i.e., the ionic concentrations of suspensions of Rehage et al. were rather high whereas our samples were deionized completely by the ion-exchange resins.
REFERENCES 1. Okubo, T., J. Amer. Chem. Soc. 109, 1913 (1987). 2. Okubo, T., J. Phys. Chem. 91, 1977 (1987). 3. Okubo, T., J. Chem. Soc. Faraday Trans. i 84, 703 (1988). Journalof ColloidandInterfaceScience,Vol. 135,No. 1, March1, 1990
4. Okubo, T., Macromolecules, 22, 1818 (1989). 5. Okubo, T., Kitano, H., Ishiwatari, T., and Ise, N., Proc. R. Soc. London Ser. A 366, 81 (1979). 6. Okubo, T., Biophys. Chem. 111, 425 (1980). 7. Okubo, T., and Enokida, A., J. Chem. Soc. Faraday Trans. 1 79, 1639 (1983). 8. Okubo, T., Hongyo, K., and Enokida, A., J. Chem. Soc. Faraday Trans. 1 80, 2087 (1984). 9. Kitano, H., Hasegawa, J., Iwai, S., and Okubo, T., Polym. Bull. (Berlin) 16, 89 (1986). 10. Okubo, T., and Ise, N., Polym. Bull. (Berlin) 1, 109 (1978). 11. Sawamoto, M., Higashimura, T., Enokida, A., and Okubo, T., Polym. Bull. (Berlin) 16, 89 (1986). 12. Okubo, T., "Dynamic Aspects of Polyelectrolytes and Biomembranes" (F. Oosawa, Ed.), p. 111. Kodansha, Tokyo, 1982. 13. Okubo, T., MakromoL Chem. SuppL 14, 161 (1985). 14. Kitano, H., Hasegawa, J., Iwai, S., and Okubo, T., J. Phys. Chem. 90, 6281 (1986). 15. Okubo, T., J. Chem. Soc. Faraday Trans. 1 84, 3567 (1988). 16. Okubo, T., Kitano, H., and lwai, S., J. Chem. Soc. Faraday Trans. 1 84, 4317 (1988). 17. Okubo, T., Maeda, Y., and Kitano, H., J. Phys. Chem., 93, 372 (1989). 18. Heckmann, K., Z. Phys. Chem., N. F. 9, 318 (1959). 19. G/Stz, K. G., and Heckmann, K., J, Colloid Sci. 13, 266 (1958). 20. Schindewolf, U., Z. Elektrochem. 58, 697 (1954). 21. Eigen, M., and Schwarz, G., J. Colloid Sci. 12, 181 (1957). 22. Schwarz, G., Z. Phys. Chem., N. F. 19, 286 (1959). 23. Heckmann, K., and G6tz, K. G., Z. Elektrochem. 62, 281 (1958). 24. GiStz, K. G., Z ColloidSci. 20, 289 (1965). 25. Kern, E. E., and Anderson, D. K., J, Polym. Sci. Part A1 6, 2765 (1968). 26. Ottewill, R. H., and Rance, D. G., Croat. Chim. Acta 50, 65 (1977). 27. Okubo, T. and Aotani, S., Colloid Polym. Sci. 266, 1049 (1988). 28. Rath, E. J., Evanco, M. A., Fredericks, R. J., and Reimschuessel, P. C., J. Polym. Sci. Part A2 10, 1337 (1972). 29. Jennings, B. R., and Oaldey, D. M., AppL Opt. 21, 1519 (1982). 30. Oakley, D. M., Jennings, B. R., Waterman, D. R., and Fairey, R. C., J. Phys. E 15, 1077 (1982). 31. Jennings, B. R., and Ridler, P. J., Proc. R. Soc. London Ser. A 411, 225 (1987). 32. Perrin, F., J. Phys. Radium. 5, 497 (1934). 33. Hachisu, S., and Kobayashi, Y., J. Colloid Interface Sci. 46, 470 (1974).
NOTES 34. Pieranski, P., Contemp. Phys. 24, 25 (1983). 35. Okubo, T., Accounts Chem. Res. 21, 281 (1988). 36. Barenes, C. J., Chan, D. Y. C., Everett, D. H., and Yates, D. E., J. Chem. Soc. Faraday Trans. 2 74, 136 (1978). 37. Giordano, R., Maisano, G., Mallamace, F., Micali, N., and Wanderlingh, F., J. Chem. Phys. 75, 4770 (1981). 38. Drifford, M., and Dalbiez, P., J. Phys. Chem. 88, 5368 (1984). 39. Shaw, J. N., and Ottewill, R. H., Nature (London) 208, 681 (1984). 40. Goff, J. R., and Luner, P., J. Colloid Interface Sci. 99, 468 (1984). 4i. Okubo, T., at. Phys. Chem., 93, 4352 (1989). 42. Angel, M., Hoffmann, H., Huber, G., and Rehage, H., Bet. Bunsenges. Phys. Chem. 92, 10 (1988).
303 TSUNEO OKUBO 1
Department of Polymer Chemistry Kyoto University Kyoto 606, Kyoto, Japan TETSUOSHIMIZU R & D Department Daikin Industries, Ltd. Settsu 566, Osaka, Japan Received March 28, 1989; accepted June 5, 1989
To whom correspondence and reprint requests should be addressed.
JournalofColloidandInterfaceScience,Vol.135,No. 1, March1, 1990