Influence of molecular structure on the size, shape, and nanostructure of nonionic CnEm surfactant micelles

Faheem N. Padia, Mohammed Yaseen, Barbara Gore, Sarah Rogers, Gordon Bell, Jian R. Lu

Research output: Contribution to journalArticle

Abstract

Nonionic alkyl ethoxylates (CnEm) have been extensively studied for their adsorption, aggregation, and solubilization individually and in small groups. In this work, we report a more systematic study of the effects of alkyl chain (tail) and ethoxylate (head) length on the size, shape, and extent of intermixing within the CnEm micelles in aqueous solution. Data from small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) were combined to undertake the structural characterization of micelles formed from the two separate series of surfactants CnE6 (n = 10, 12, 14) and C12Em (m = 5, 6, 8, 10, 12). The micellar core volume (Vcore) could be well determined with reasonable accuracy and linked to the hydrophilic–lipophilic balance (HLB) of the surfactant, with a sharp size and shape transition occurring around HLB = 12.5. NOESY NMR results revealed protrusions of the terminal methylene groups into the ethoxylate shell, thus providing direct experimental evidence for the phenomenon of “roughness” or intermixing of the core–shell interface. These detailed studies are compared with previous investigations on this model surfactant system.
Original languageEnglish
Pages (from-to)179-188
Number of pages10
JournalThe Journal of Physical Chemistry B
Volume118
Issue number1
DOIs
Publication statusPublished - 4 Dec 2013
Externally publishedYes

Cite this

Padia, Faheem N. ; Yaseen, Mohammed ; Gore, Barbara ; Rogers, Sarah ; Bell, Gordon ; Lu, Jian R. / Influence of molecular structure on the size, shape, and nanostructure of nonionic CnEm surfactant micelles. In: The Journal of Physical Chemistry B. 2013 ; Vol. 118, No. 1. pp. 179-188.
@article{bc35463eba074512a26e1fd3fbcb5970,
title = "Influence of molecular structure on the size, shape, and nanostructure of nonionic CnEm surfactant micelles",
abstract = "Nonionic alkyl ethoxylates (CnEm) have been extensively studied for their adsorption, aggregation, and solubilization individually and in small groups. In this work, we report a more systematic study of the effects of alkyl chain (tail) and ethoxylate (head) length on the size, shape, and extent of intermixing within the CnEm micelles in aqueous solution. Data from small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) were combined to undertake the structural characterization of micelles formed from the two separate series of surfactants CnE6 (n = 10, 12, 14) and C12Em (m = 5, 6, 8, 10, 12). The micellar core volume (Vcore) could be well determined with reasonable accuracy and linked to the hydrophilic–lipophilic balance (HLB) of the surfactant, with a sharp size and shape transition occurring around HLB = 12.5. NOESY NMR results revealed protrusions of the terminal methylene groups into the ethoxylate shell, thus providing direct experimental evidence for the phenomenon of “roughness” or intermixing of the core–shell interface. These detailed studies are compared with previous investigations on this model surfactant system.",
author = "Padia, {Faheem N.} and Mohammed Yaseen and Barbara Gore and Sarah Rogers and Gordon Bell and Lu, {Jian R.}",
year = "2013",
month = "12",
day = "4",
doi = "10.1021/jp409808c",
language = "English",
volume = "118",
pages = "179--188",
journal = "The Journal of Physical Chemistry B",
issn = "1520-6106",
publisher = "ACS Publications",
number = "1",

}

Influence of molecular structure on the size, shape, and nanostructure of nonionic CnEm surfactant micelles. / Padia, Faheem N.; Yaseen, Mohammed; Gore, Barbara; Rogers, Sarah; Bell, Gordon; Lu, Jian R.

In: The Journal of Physical Chemistry B, Vol. 118, No. 1, 04.12.2013, p. 179-188.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Influence of molecular structure on the size, shape, and nanostructure of nonionic CnEm surfactant micelles

AU - Padia, Faheem N.

AU - Yaseen, Mohammed

AU - Gore, Barbara

AU - Rogers, Sarah

AU - Bell, Gordon

AU - Lu, Jian R.

PY - 2013/12/4

Y1 - 2013/12/4

N2 - Nonionic alkyl ethoxylates (CnEm) have been extensively studied for their adsorption, aggregation, and solubilization individually and in small groups. In this work, we report a more systematic study of the effects of alkyl chain (tail) and ethoxylate (head) length on the size, shape, and extent of intermixing within the CnEm micelles in aqueous solution. Data from small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) were combined to undertake the structural characterization of micelles formed from the two separate series of surfactants CnE6 (n = 10, 12, 14) and C12Em (m = 5, 6, 8, 10, 12). The micellar core volume (Vcore) could be well determined with reasonable accuracy and linked to the hydrophilic–lipophilic balance (HLB) of the surfactant, with a sharp size and shape transition occurring around HLB = 12.5. NOESY NMR results revealed protrusions of the terminal methylene groups into the ethoxylate shell, thus providing direct experimental evidence for the phenomenon of “roughness” or intermixing of the core–shell interface. These detailed studies are compared with previous investigations on this model surfactant system.

AB - Nonionic alkyl ethoxylates (CnEm) have been extensively studied for their adsorption, aggregation, and solubilization individually and in small groups. In this work, we report a more systematic study of the effects of alkyl chain (tail) and ethoxylate (head) length on the size, shape, and extent of intermixing within the CnEm micelles in aqueous solution. Data from small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) were combined to undertake the structural characterization of micelles formed from the two separate series of surfactants CnE6 (n = 10, 12, 14) and C12Em (m = 5, 6, 8, 10, 12). The micellar core volume (Vcore) could be well determined with reasonable accuracy and linked to the hydrophilic–lipophilic balance (HLB) of the surfactant, with a sharp size and shape transition occurring around HLB = 12.5. NOESY NMR results revealed protrusions of the terminal methylene groups into the ethoxylate shell, thus providing direct experimental evidence for the phenomenon of “roughness” or intermixing of the core–shell interface. These detailed studies are compared with previous investigations on this model surfactant system.

U2 - 10.1021/jp409808c

DO - 10.1021/jp409808c

M3 - Article

VL - 118

SP - 179

EP - 188

JO - The Journal of Physical Chemistry B

JF - The Journal of Physical Chemistry B

SN - 1520-6106

IS - 1

ER -