emerging area of gemini surfactants is reviewed. The differences
in structure/property relationships between gemini and compa-
rable conventional surfactants are described and discussed in
terms of their predicted performance properties. Supportive per-
formance data are enumerated.
JSD 1, 547–554 (1998).
The literature, including patents, describing the
emulsification, foaming, gemini, irritation, surfactants, syner-
Critical micelle concentration, dispersion,
Gemini surfactants contain two hydrophilic groups and
two (sometimes three) hydrophobic groups. Although
patents on surfactants of this structure have existed since
1935 (1), interest has been intense only in the past several
years as a result of a report (2) which pointed out that these
surfactants could be more surface-active by orders of mag-
nitude than comparable conventional surfactants contain-
ing a similar single hydrophilic group and a single hy-
drophobic group. As a result, numerous papers have
appeared in the chemical literature describing the funda-
mental properties of gemini surfactants (3–62) as well as,
especially in the last few years, a flurry of patents covering
all the electrical charge types of surfactants: anionics
(63–77), cationics (78–84), zwitterionics (84–90), and non-
GEMINI VS. CONVENTIONAL SURFACTANTS:
DIFFERENCES IN FUNDAMENTAL PROPERTIES
Compared to their conventional analogs, gemini surfac-
tants possess: (i) much lower critical micelle concentration
(CMC) values (a measure of their tendency to form mi-
celles), (ii) much lower C20values (a measure of their ten-
dency to adsorb at an interface), (iii) closer packing of the
hydrophobic groups, and 4(iv) stronger interaction with
*To whom correspondence should be addressed.
oppositely charged surfactants at the aqueous solution/air
interface. In addition, they are more soluble in water and
some geminis exhibit unique rheological properties.
CMC and C20values. CMC values in aqueous media and
C20values [the surfactant concentration in the aqueous
phase that produces a 20 dyne/cm reduction in the surface
tension of the solvent (100)] are shown in Table 1, together
with some values for comparable conventional surfactants.
(Note: Methylene groups between two hydrophilic groups,
such as an oxygen atom up to four carbon atoms away
from a second hydrophilic group, generally are equivalent
to one-half of a methylene group in a straight alkyl chain.)
It is apparent from the data in Table 1 that geminis can
have CMC values one to two orders of magnitude smaller
and C20values two to three orders of magnitude smaller
than those of comparable conventional surfactants. This is
claimed (91) also for zwitterionic geminis of structure
The length and structure of the linkage between the two
hydrophilic groups also determines the CMC and C20
values. For the cationic series C10H21N+(CH3)2(CH2)mN+-
(CH3)2C10H21·2Br−(17) and C12H25N+(CH3)2(CH2)mN+-
(CH3)2C12H25·2Br−(16) it has been found that the CMC
value increases with m to a maximum at m equals ca. 4 and
then decreases. The cause of the decrease, it is suggested
(16), is that once the hydrophobic polyethylene group
reaches sufficient length, it penetrates into the interior of
the micelle and thus is removed from contact with the aque-
ous phase. The smallest CMC and C20values appear to
arise with linkages that are short, slightly hydrophilic
(just capable of hydrogen bonding with water), and, if
hydrophobic, flexible. Thus, for geminis with similar
alkyl chains and the following linkages, the CMC
values increase in the order: –CH2CH2OCH2CH2– <
–CH2CHOHCH2CH2– < –CH2CHOHCHOHCH2– <
–CH2CH2CH2CH2– < p–CH2C6H4CH2– (Table 1), and
both the CMC and C20values increase in the order:
O < –O(CH2CH2O)3– (25). The rigidity of the hydrophobic
Copyright © 1998 by AOCS PressJournal of Surfactants and Detergents, Vol. 1, No. 4 (October 1998)547
Milton J. Rosena,* and David J. Tracyb
aSurfactant Research Institute, Brooklyn College of the City University of New York, Brooklyn, New York 11210,
and bSurfactants and Performance Ingredients, Rhodia, Inc., Cranbury, New Jersey 08512-7500
Selve, Nonionic Amphiphilic Compounds from Aspartic
and Glutamic Acids as Structural Mimics of Lecithins, Ibid.
54. Rosen, M.J., and L Liu, Surface Activity and Premicellar Ag-
gregation of Some Novel Diquaternary Gemini Surfactants,
Ibid. 73:885–890 (1996).
55. Kim, T.-S., T. Kida, Y. Nakatsuji, T. Hirao, and I. Ikeda, Sur-
face-Active Properties of Novel Cationic Surfactants with
Two Alkyl Chains and Two Ammonio Groups, Ibid.
56. Jaeger, D.A., and E.L. Brown, Double-chain Surfactants with
Two Carboxylate Head Groups That Form Vesicles, Lang-
muir 12:1976–1980 (1996).
57. Perez, L., J.L. Torres, A. Manresa, C. Solans, and Ma.R. In-
fante, Synthesis, Aggegation, and Biological Properties of a
New Class of Gemini Cationic Amphiphilic Compounds
from Arginine, bis (Args), Ibid. 12:5296–5301 (1996).
58. Danino, D., Y. Talmon, and R. Zana, Vesicle-to-Micelle
Transformation in Systems Containing Dimeric Surfactants,
J. Colloid Interface Sci. 185:84–93 (1997).
59. Duivenvoorde, F.L., M.C. Feiters, S.J. van der Gaast, and
J.B.F.N. Engberts, Synthesis and Properties of Di-n-dodecyl-
α,ω-alkyl Bisphosphate Surfactants, Langmuir 13:3737-3743
60. Zana, R., M. In, H. Levy, and G. Duportail, Alkanediyl-
bis(dimethylalkylammonium bromide). 7. Fluorescence
Probing Studies of Micelle Micropolarity and Microviscos-
ity, Ibid. 13:5552–5557 (1997).
61. Rico-Lattes, I., and A. Lattes, Synthesis of New Sugar-Based
Surfactants Having Biological Applications: Key Role
of Their Self-Association, Colloids Surf. A 123-124:37–48
62. Castro, M.J.L., J. Kovensky, and A.F. Cirelli, Gemini Surfac-
tants from Alkyl Glucosides, Tetrahedron Lett. 38:3995–3998
63. Reitz, G., and G. Boehmke, Great Britain Patent 1,503,280
64. Behler, A., R. Piorr, and M. Schaefer, U.S. Patent, 4,936,551
65. Okahara, M., and A. Masuyama, U.S. Patent 5,160,450 (1992).
66. Gruber, B., Ger. Offen. DE 4,232,414 A1 (1994).
67. Wangemann, F. Ger. Offen. DE 4,321,022 A1 (1995).
68. Raths, H.C., and W.E. Noack, Ger. Offen. DE 4,401,565
69. Kaiser, R.J., U.S. Patent 5,507,863 (1996).
70. Kaiser, R.J., U.S. Patent 5,487,778 (1996).
71. Varadaraj, R., and S. Zushma, U.S. Patent 5,585,516 (1996).
72. Varadaraj, R., and S. Zushma, U.S. Patent 5,493,050 (1996).
73. Kaiser, R.J., U.S. Patent 5,599,933 (1997).
74. Okano, T., M. Fukuda, J. Tanabe, M. Ono, Y. Akabane, H.
Takahashi, N. Egawa, T. Sakotani, H. Kanao, and Y.
Yoneyanna, U.S. Patent 5,681,803 (1997).
75. Raths, H., Ger. Offen. DE 19,622,612 (1997).
76. Tracy, D.J., R. Li, and J.M. Ricca, U.S. Patent 5,710,121 (1998).
77. Kitsubi, T., M. Uno, K. Kita, Y. Fujikura, A. Nakano, M.
Tosaka, K. Yahagi, S. Tamura, and K. Maruta, U.S. Patent
78. McConnell, R.B., U.S. Patent 3,855,235 (1974).
79. McConnell, R.B., U.S. Patent 3,887, 476 (1975).
80. Login, R.B., U.S. Patent 4,764,306 (1988).
81. Login, R.B., U.S. Patent 4,734,277 (1988).
82. Login, R.B., U.S. Patent 4,812,263 (1989).
83. Chauhuri, R.K., D.J. Tracy, and R.B. Login, U.S. Patent
84. Li, J., N. Dahanayake, R.L. Reierson, and D.J. Tracy, U.S.
Patent 5,643,498 (1997).
85. Bersworth, F., U.S. Patent 2,524,218 (1950).
86. Bersworth, F., U.S. Patent 2,530,147 (1950).
87. Bersworth, F., U.S. Patent 2,532,391 (1950).
88. Schmitz, A. G.B. Patent 1,149,140 (1967).
89. Nakamo, A., T. Kitsuki, K. Kita, and M. Asuga, International
Patent PCT WO 96/01800 (1996).
90. Kwetkat, K., International Patent PCT WO 97/31890 (1997).
91. Li, J., M. Dahanayake, R.L. Reierson, and D.J. Tracy, U.S.
Patent 5,656,586 (1997).
92. Briggs, C.B., and A.R. Pitts, U.S. Patent 4,892,806 (1990).
93. Gorelli-Calvet, R., F. Brisset, J. Rico, A. Lattes, and L. Gode-
froy, U.S. Patent 5,403,922 (1995).
94. Adams, K., Eur. Pat. Appl. EPO 688781 (1995).
95. Scheibel, J., D.S. Connor, and E.Y. Fu, U.S. Patent 5,534,197
96. Connor, D.S., Y. Fu, and J.J. Scheibel, U.S. Patent 5,512,699
97. Tsubone, K., H. Nishio, and M. Kusumaru, Jpn. Kokai
Tokkyo Koho JP 08,291,040 (1996).
98. Tsubone, K., H. Nishio, and M. Kusumaru, Jpn. Kokai
Tokkyo Koho JP 08,319,262 (1996).
99. Wong, S., U.S. Patent 5,622,938 (1997).
100. Rosen, M.J., Surfactants and Interfacial Phenomena, 2nd edn.,
John Wiley, New York, 1989, pp. 84–85.
101. Draves, C.Z., and R.G. Clarkson, A New Method for the
Evaluation of Wetting Agents, Amer. Dyestuff Rept. 20:
102. Rosen, M.J., and Z.H. Zhu, Enhancement of Wetting Proper-
ties of Water- Insoluble Surfactants via Solubilization, J. Am.
Oil Chem. Soc. 70:65 (1993).
103. Dreja, M., and B. Tieke, Polymerization of Styrene in Ternary
Microemulsion Using Cationic Gemini Surfactants, Langmuir
[Received June 1, 1998; accepted September 1, 1998]
Professor Rosen is Director of the Surfactant Research Institute
at Brooklyn College of the City University of New York. He has
published six books and well over 100 research papers in the area
of surfactants. He acts as consultant and frequently invited lec-
turer in the field and has served on the advisory or editorial
boards of several leading journals.
Dr. David Tracy is a Scientist Fellow at Rhodia Inc. where he
is responsible for research and development of new products, in-
cluding gemini surfactants. He graduated with honors, receiv-
ing a B.A. in chemistry from Thomas More College and an M.S.
and Ph.D. in organic chemistry from the University of Illinois.
Throughout his thirty-year career he also held various R&D po-
sitions at GAF before joining Rhodia Inc. in 1990.
Journal of Surfactants and Detergents, Vol. 1, No. 4 (October 1998)