Characterization of Wormlike Pentaoxyethylene Dodecyl Ether C12E5 Micelles Containing n-Dodecanol

Miyake, Maiko; Einaga, Yoshiyuki

doi:10.1295/polymj.pj2006276

Cited by 6 publications

(32 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1=2 in the range of c examined, as in the case of the previous findings for the micelles formed with single surfactant of various type, [9][10][11][12][13][14] for those formed with binary C i E j mixtures, 15,16 and the micelles containing n-dodecanol or n-octanol. [2][3][4][5][6] These results are in good correspondence with simple theoretical predictions derived from the thermodynamic treatments of multiple equilibria among micelles of various aggregation numbers. 7,[27][28][29] The increase in M w ðcÞ with increasing c is also consistent with the findings by Menge et al 30,31 for the C 12 E 5 + n-decane micelles.…”

Section: Analysis Of Sls Datasupporting

confidence: 79%

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Ochi

Matsue

Einaga

2008

Polym J

Self Cite

View full text Add to dashboard Cite

Wormlike micelles of the surfactant hexaoxyethylene tetradecyl and decyl ethers C 14 E 6 and C 10 E 6 were characterized by static (SLS) and dynamic light scattering (DLS) experiments to examine effects of uptake of n-dodecane on the micellar characteristics. The SLS results have been successfully analyzed by the light scattering theory for micelle solutions to yield the molar mass M w ðcÞ as a function of concentration c along with the cross-sectional diameter d of the micelle. The apparent hydrodynamic radius R H,app ðcÞ determined by DLS as a function of c has also been successfully analyzed by the fuzzy cylinder theory which takes into account the hydrodynamic and direct collision interactions among micelles, providing us with the values of the stiffness parameter À1 . It has been found that although the micellar length L w increases with increasing surfactant mass concentration c and the d and À1 values increase with increasing n-dodecane content w d , as in the case of various C i E j micelles containing n-alcohol, the values of M w , L w , and R H,app for all the micelles examined decrease or hardly vary with increasing w d contrary to the micelles containing n-alcohol. This finding may reflect the fact that the addition of n-dodecane into the micelles weakens hydrophilic interactions among polyoxyethylene chains of the surfactant molecules and water, making the micelles unstable, and then leading to collapse them into micelles of the smaller size. In this series of work on micelle solutions of nonionic surfactant polyoxyethylene alkyl ethers H(CH 2 ) i (OCH 2 CH 2 ) j -OH (abbreviated C i E j ), we have characterized the wormlike C i E j micelles with various i and j containing n-alcohols, ndodecanol or n-octanol, 1-5 and n-dodecane 6 by static (SLS) and dynamic light scattering (DLS) measurements in order to explore effects of uptake of n-alcohol or n-dodecane into the micelles on the micellar characteristics. It has been demonstrated that the SLS results (the excess Rayleigh ratio) as a function of surfactant concentration c are successfully analyzed by a molecular thermodynamic theory 7,8 formulated with the wormlike spherocylinder model to provide us with molar mass M w ðcÞ of the micelle at a specified c along with the crosssectional diameter d of the spherocylinder, as in the case of the micelle solutions of pure C i E j and binary C i E j mixtures. 9-16The DLS results have been also successfully analyzed in a similar fashion to the micelle solutions of pure C i E j and their binary mixtures with the aid of the fuzzy cylinder theory, [17][18][19][20] thereby yielding the concentration-dependent micellar growth by separating contributions of the enhancement of hydrodynamic interactions among micelles with increasing concentration to the apparent hydrodynamic radius R H,app , which is directly obtained from DLS experiment. The analyses have yielded the values of the stiffness parameter À1 and shown that the molar mass M w dependence of the hydrodynamic radius R H is quantitatively represented by the ...

show abstract

Section: Analysis Of Sls Datasupporting

confidence: 79%

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Ochi

Matsue

Einaga

2008

Polym J

Self Cite

View full text Add to dashboard Cite

show abstract

“…A series of the data points for the latter near w d ¼ 0:028 are the results by Hellweg and von Klitzing. 67 We find that at small w d , the cloud point curve shift to lower temperatures with increasing w d and then shift to higher temperatures at larger w d in contrast to the case of the micelle solutions containing n-alcohol [31][32][33][34][35] for which the phase boundaries monotonically shift to lower temperatures as the alcohol content increases. In panel a of Figure 25, the emulsification failure boundary schematically shown by the surface enclosed by dashed and dotted lines indicates that too much n-dodecane can not be included in the C 12 E 5 micelles at any T and w d .…”

Section: Effects Of the Uptake Of N-alcohol And N-alkanementioning

confidence: 62%

“…They have shown that the apparent molar mass M app of the wormlike micelles formed in the L 1 phase increases with c in the range of small c, passing through a maximum, and then decreases with increasing c at higher c. Here, M app includes two contributions, i.e., concentration-dependent molar mass M w ðcÞ of the micelles and concentration dependent structure factor Sðc; q ¼ 0Þ (q the magnitude of scattering vector) which reflects thermodynamic interactions among micelles. We have also investigated solution properties of the wormlike micelles of various C i E j containing n-dodecanol, -octanol, and n-dodecane, [32][33][34][35][36][37] by applying the same technique as in the case of the micelles of C i E j and their mixtures described above.…”

Section: Effects Of the Uptake Of N-alcohol And N-alkanementioning

confidence: 99%

“…[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] In the work, we have been able to determine the concentration-dependent characteristics of the micelles by separating contributions of the intermicellar thermodynamic and hydrodynamic interactions to the SLS and DLS results with the aid of the corresponding theories. We have determined the weight-average molar mass M w of the micelles as a function of surfactant mass concentration c along with the cross-sectional diameter d from the SLS data by using a molecular thermodynamic theory 21,38 formulated with the wormlike spherocylinder model.…”

mentioning

confidence: 99%

“…The studies have been extended to the C i E j micelles containing n-dodecanol, n-octanol, and ndodecane in order to explore effects of uptake of n-alcohol and n-alkane into the micelles on the micellar characteristics. [31][32][33][34][35][36][37] The SLS and DLS results were successfully analyzed in a similar fashion to the micelle solutions of single C i E j and their binary mixtures.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Wormlike Micelles of Polyoxyethylene Alkyl Ethers CiEj

Einaga¹

2009

Polym. J.

Self Cite

View full text Add to dashboard Cite

It is demonstrated that wormlike micelles of nonionic surfactants polyoxyethylene alkyl ethers H(CH 2 ) i (OCH 2 CH 2 ) j OH (C i E j ) have been successfully characterized by static (SLS) and dynamic light scattering (DLS) measurements and viscometry with the aid of the theories developed so far in the field of polymer solution studies, i.e., a molecular thermodynamic theory for light scattering, chain statistical and hydrodynamic theories for semi-flexible polymers. The results for the excess Rayleigh ratio, radius of gyration, hydrodynamic radius, and intrinsic viscosity have been shown to be well represented by the theories based on a wormlike spherocylinder model. Some salient features found for the micelles of C i E j with various i or j, their binary mixtures, and the micelles including n-alcohol and n-alkane are discussed. The nonionic surfactant polyoxyethylene mono-alkyl ether H(CH 2 ) i (OCH 2 CH 2 ) j OH, (abbreviated C i E j ), exhibits a wide variety of phases in aqueous solution as a function of surfactant concentration and temperature. 1,2 Here, i and j denote the number of methylene groups in the alkyl group and that of repeating units in the oxyethylene group, respectively. At dilute regime, the C i E j + water binary system forms an isotropic phase, that is so-called L 1 phase, which consists of micelles formed with the amphiphilic molecules and water. The system exhibits the LCST behavior; the micellar solutions are phaseseparated into two phases at high temperatures. It is now well established that the micelles grow in size with increasing concentration and raising temperature, in particular to a greater extent when approaching the phase boundary, assuming threadlike or wormlike cylindrical shape. (See Figure 1.) The wormlike micelles have been visually shown by the cryo-TEM observation, 3 in which in the process of micellar growth, threadlike or polymer-like micelles are evolved in the solutions examined. The micelles are, thus, sometimes called ''living'' or ''equilibrium'' polymers in a sense that the linear macromolecules formed can break and recombine.The polymerlike micelles have certain similarities to real polymers and then their solution properties are analogous to those of real polymer solutions. They have been, thus, rather widely studied to characterize their shape and size by employing the theoretical concepts and experimental methods developped in the polymer solution studies, such as static (SLS) and dynamic light scattering (DLS), [3][4][5][6][7][8][9][10][11][12] small-angle neutron scattering (SANS), 13-15 viscometry, 15,16 pulsed-field gradient NMR, 4-7 and so forth. However, solutions of polymer-like micelles are essentially different from those of real polymers. The molar mass of the micelle, i.e., the aggregation number, varies with surfactant concentration, temperature, and other solvent conditions. The average value and distribution of the micellar size are determined by multiple chemical equilibrium among micelles with various aggregation numbers. Although the equi...

show abstract

Variation of Characteristics of Pentaoxyethylene Decyl C₁₀E₅ and Hexaoxyethylene Tetradecyl C₁₄E₆ Ether Micelles with Uptake of n-Octanol

2007

Self Cite

View full text Add to dashboard Cite

Wormlike micelles of the surfactant pentaoxyethylene decyl C10E5 and hexaoxyethylene tetradecyl C14E6 ethers were characterized by static (SLS) and dynamic light scattering (DLS) experiments to examine effects of uptake of n-octanol on the micellar characteristics. The SLS results have been successfully analyzed by the light scattering theory for micelle solutions to yield the molar mass Mw(c) as a function of concentration c along with the cross-sectional diameter d of the micelle. The apparent hydrodynamic radius RH,app(c) determined by DLS as a function of c has also been successfully analyzed by a fuzzy cylinder theory which takes into account the hydrodynamic and direct collision interactions among micelles, providing us with the values of the stiffness parameter lambda(-1). It has been found that the micellar length Lw increases with increasing surfactant weight fraction ws and increasing n-octanol content wo in the micelles or with raising temperature T. The values of d and lambda(-1) are found to increase with increasing wo, whereas the spacing s between hydrophilic tails of adjacent surfactant molecules on the micellar surface decreases with increasing wo. Comparison with our previous results for the C10E5 and C14E6 micelles containing n-dodecanol has revealed the salient features in change of the micellar characteristics with uptake of n-alcohols as follows: (i) The Lw values increase more significantly for the C14E6 micelles containing n-dodecanol than those containing n-octanol, whereas Lw of the C10E5 micelles increases by including n-dodecanol and n-octanol without a significant difference for the two alcohols. (ii) The values of d and lambda(-1) of the C10E5 and C14E6 micelles increase with uptake of n-octanol and n-dodecanol into the micelles. They are larger for the C10E5 micelles than for the C14E6 micelles, and their increase with alcohol content is less significant for the C14E6 micelles in comparison with the C10E5 micelles. (iii) The s values of the C10E5 and C14E6 micelles decrease with uptake of n-octanol and n-dodecanol into the micelles. They are somewhat larger in the latter micelles than in the former. (iv) The variation in d, s, and lambda(-1) with uptake of n-alcohol occurs with no difference in the effects for the two alcohols n-octanol and n-dodecanol.

show abstract

Characterization of Wormlike Pentaoxyethylene Dodecyl Ether C12E5 Micelles Containing n-Dodecanol

Cited by 6 publications

References 37 publications

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Wormlike Micelles of Polyoxyethylene Alkyl Ethers CiEj

Variation of Characteristics of Pentaoxyethylene Decyl C₁₀E₅ and Hexaoxyethylene Tetradecyl C₁₄E₆ Ether Micelles with Uptake of n-Octanol

Contact Info

Product

Resources

About

Characterization of Wormlike Pentaoxyethylene Dodecyl Ether C12E5 Micelles Containing n-Dodecanol

Cited by 6 publications

References 37 publications

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Change in Characteristics of Wormlike Micelles of Hexaoxyethylene Tetradecyl and Decyl Ethers (C14E6 and C10E6) with Uptake of n-Dodecane

Wormlike Micelles of Polyoxyethylene Alkyl Ethers CiEj

Variation of Characteristics of Pentaoxyethylene Decyl C10E5 and Hexaoxyethylene Tetradecyl C14E6 Ether Micelles with Uptake of n-Octanol

Contact Info

Product

Resources

About

Variation of Characteristics of Pentaoxyethylene Decyl C₁₀E₅ and Hexaoxyethylene Tetradecyl C₁₄E₆ Ether Micelles with Uptake of n-Octanol