Wormlike Micelles of a Cationic Surfactant in Polar Organic Solvents: Extending Surfactant Self-Assembly to New Systems and Subzero Temperatures
Agrawal, NR (Agrawal, Niti R.)[ 1 ]; Yue, X (Yue, Xiu)[ 1,2 ]; Feng, YJ (Feng, Yujun)[ 3 ]; Raghavan, SR (Raghavan, Srinivasa R.)[ 1 ]
刊名LANGMUIR
2019
卷号35期号:39页码:12782-12791
ISSN号0743-7463
DOI10.1021/acs.langmuir.9b02125
英文摘要

Wormlike micelles (WLMs) are long, flexible cylindrical chains formed by the self-assembly of surfactants in semidilute solutions. Scientists have been fascinated by WLMs because of their similarities to polymers, while at the same time, the viscoelastic properties of WLM solutions have made them useful in a variety of industrial applications. To date, most studies on WLMs have been performed in water (i.e., a highly polar liquid), while there are a few examples of "reverse" WLMs in oils (i.e., highly nonpolar liquids). However, in organic solvents with lower polarity than water such as glycerol, formamide, and ethylene glycol, there have been no reports of WLMs thus far. Here, we show that it is indeed possible to induce a long-tailed cationic surfactant to assemble into WLMs in several of these solvents. To form WLMs, the surfactant is combined with a "binding" salt, i.e., one with a large organic counterion that is capable of binding to the micelles. Examples of such salts include sodium salicylate and sodium tosylate, and we find self-assembly to be maximized when the surfactant and salt concentrations are near-equimolar. Interestingly, the addition of a simple, inorganic salt such as sodium chloride (NaCl) to the same surfactant does not induce WLMs in polar solvents (although it does so in water). Thus, the design rules for WLM formation in polar solvents are distinct from those in water. Aqueous WLMs have been characterized at temperatures from 25 degrees C and above, but few studies have examined WLMs at much lower (e.g., subzero) temperatures. Here, we have selected a surfactant with a very low Krafft point (i.e., the surfactant does not crystallize out of solution upon cooling due to a cis-unsaturation in its tail) and a low-freezing solvent, viz. a 90/10 mixture of glycerol and ethylene glycol. In these mixtures, we find evidence for WLMs that persist down to temperatures as low as -20 degrees C. Rheological techniques as well as small-angle neutron scattering (SANS) have been used to characterize the WLMs under these conditions. Much like their aqueous counterparts, WLMs in polar solvents show viscoelastic properties, and accordingly, these fluids could find applications as synthetic lubricants or as improved antifreezing fluids.

WOS记录号WOS:000488993300021
内容类型期刊论文
源URL[http://ir.xjipc.cas.cn/handle/365002/7155]  
专题新疆理化技术研究所_环境科学与技术研究室
作者单位1.Sichuan Univ, State Key Lab Polymer Mat Engn, Polymer Res Inst, Chengdu 610065, Sichuan, Peoples R China
2.Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Urumqi 830011, Peoples R China
3.Univ Maryland, Dept Chem & Biomol Engn, College Pk, MD 20742 USA
推荐引用方式
GB/T 7714
Agrawal, NR ,Yue, X ,Feng, YJ ,et al. Wormlike Micelles of a Cationic Surfactant in Polar Organic Solvents: Extending Surfactant Self-Assembly to New Systems and Subzero Temperatures[J]. LANGMUIR,2019,35(39):12782-12791.
APA Agrawal, NR ,Yue, X ,Feng, YJ ,&Raghavan, SR .(2019).Wormlike Micelles of a Cationic Surfactant in Polar Organic Solvents: Extending Surfactant Self-Assembly to New Systems and Subzero Temperatures.LANGMUIR,35(39),12782-12791.
MLA Agrawal, NR ,et al."Wormlike Micelles of a Cationic Surfactant in Polar Organic Solvents: Extending Surfactant Self-Assembly to New Systems and Subzero Temperatures".LANGMUIR 35.39(2019):12782-12791.
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