Unprecedented microemulsion boosting effect induced by a charged diblock copolymer: bending modulus and curvature frustration of the surfactant film

作者：Marchal Frederic; Guenoun Patrick^*; Daillant Jean; Holley D Wade; Mays Jimmy W

来源：Soft Matter, 2009, 5(20): 4006-4014.

DOI：10.1039/b904990h

Single-phase microemulsions made of comparable amounts of water and alkane cannot be stabilized unless a large proportion of surfactant is used. Typically 10 to 30% nonionic surfactants such as n-alkylpolyglycol ethers are required to form such phases. Over the past 15 years, several authors have shown that this proportion can be significantly reduced by adding minute amounts of neutral diblock copolymers. However, though the surfactant film elastic properties seem to play a role in this so-called efficiency boosting effect, there is no clear agreement about the influence of the copolymer on bending properties, and about the correlation between those properties and the boosting effect. We present in this paper an original experimental occurrence of the boosting effect by using charged diblock copolymers. Based on a combination of various experimental techniques, an unprecedented swelling is evidenced and discussed in terms of variations of bending modulus. In particular an expression of the microemulsion free energy density proposed by Andelman et al. is used to correlate successfully the surfactant film bending modulus to the boosting. A curvature "frustration'' between surfactant and copolymer is also pointed out as a possible contribution to the boosting effect.

• 出版日期2009
• 单位中国地震局