Research output: Contribution to journal › Review article › peer-review
Thermodynamics, adsorption kinetics and rheology of mixed protein-surfactant interfacial layers. / Kotsmar, Cs; Pradines, V.; Alahverdjieva, V. S.; Aksenenko, E. V.; Fainerman, V. B.; Kovalchuk, V. I.; Krägel, J.; Leser, M. E.; Noskov, B. A.; Miller, R.
In: Advances in Colloid and Interface Science, Vol. 150, No. 1, 30.08.2009, p. 41-54.Research output: Contribution to journal › Review article › peer-review
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TY - JOUR
T1 - Thermodynamics, adsorption kinetics and rheology of mixed protein-surfactant interfacial layers
AU - Kotsmar, Cs
AU - Pradines, V.
AU - Alahverdjieva, V. S.
AU - Aksenenko, E. V.
AU - Fainerman, V. B.
AU - Kovalchuk, V. I.
AU - Krägel, J.
AU - Leser, M. E.
AU - Noskov, B. A.
AU - Miller, R.
PY - 2009/8/30
Y1 - 2009/8/30
N2 - Depending on the bulk composition, adsorption layers formed from mixed protein/surfactant solutions contain different amounts of protein. Clearly, increasing amounts of surfactant should decrease the amount of adsorbed proteins successively. However, due to the much larger adsorption energy, proteins are rather strongly bound to the interface and via competitive adsorption surfactants cannot easily displace proteins. A thermodynamic theory was developed recently which describes the composition of mixed protein/surfactant adsorption layers. This theory is based on models for the single compounds and allows a prognosis of the resulting mixed layers by using the characteristic parameters of the involved components. This thermodynamic theory serves also as the respective boundary condition for the dynamics of adsorption layers formed from mixed solutions and their dilational rheological behaviour. Based on experimental studies with milk proteins (β-casein and β-lactoglobulin) mixed with non-ionic (decyl and dodecyl dimethyl phosphine oxide) and ionic (sodium dodecyl sulphate and dodecyl trimethyl ammonium bromide) surfactants at the water/air and water/hexane interfaces, the potential of the theoretical tools is demonstrated. The displacement of pre-adsorbed proteins by subsequently added surfactant can be successfully studied by a special experimental technique based on a drop volume exchange. In this way the drop profile analysis can provide tensiometry and dilational rheology data (via drop oscillation experiments) for two adsorption routes - sequential adsorption of the single compounds in addition to the traditional simultaneous adsorption from a mixed solution. Complementary measurements of the surface shear rheology and the adsorption layer thickness via ellipsometry are added in order to support the proposed mechanisms drawn from tensiometry and dilational rheology, i.e. to show that the formation of mixed adsorption layer is based on a modification of the protein molecules via electrostatic (ionic) and/or hydrophobic interactions by the surfactant molecules and a competitive adsorption of the resulting complexes with the free, unbound surfactant. Under certain conditions, the properties of the sequentially formed layers differ from those formed simultaneously, which can be explained by the different locations of complex formation.
AB - Depending on the bulk composition, adsorption layers formed from mixed protein/surfactant solutions contain different amounts of protein. Clearly, increasing amounts of surfactant should decrease the amount of adsorbed proteins successively. However, due to the much larger adsorption energy, proteins are rather strongly bound to the interface and via competitive adsorption surfactants cannot easily displace proteins. A thermodynamic theory was developed recently which describes the composition of mixed protein/surfactant adsorption layers. This theory is based on models for the single compounds and allows a prognosis of the resulting mixed layers by using the characteristic parameters of the involved components. This thermodynamic theory serves also as the respective boundary condition for the dynamics of adsorption layers formed from mixed solutions and their dilational rheological behaviour. Based on experimental studies with milk proteins (β-casein and β-lactoglobulin) mixed with non-ionic (decyl and dodecyl dimethyl phosphine oxide) and ionic (sodium dodecyl sulphate and dodecyl trimethyl ammonium bromide) surfactants at the water/air and water/hexane interfaces, the potential of the theoretical tools is demonstrated. The displacement of pre-adsorbed proteins by subsequently added surfactant can be successfully studied by a special experimental technique based on a drop volume exchange. In this way the drop profile analysis can provide tensiometry and dilational rheology data (via drop oscillation experiments) for two adsorption routes - sequential adsorption of the single compounds in addition to the traditional simultaneous adsorption from a mixed solution. Complementary measurements of the surface shear rheology and the adsorption layer thickness via ellipsometry are added in order to support the proposed mechanisms drawn from tensiometry and dilational rheology, i.e. to show that the formation of mixed adsorption layer is based on a modification of the protein molecules via electrostatic (ionic) and/or hydrophobic interactions by the surfactant molecules and a competitive adsorption of the resulting complexes with the free, unbound surfactant. Under certain conditions, the properties of the sequentially formed layers differ from those formed simultaneously, which can be explained by the different locations of complex formation.
KW - Adsorption kinetics
KW - Liquid interfaces
KW - Protein-surfactant mixtures
KW - Surface dilational rheology
KW - Surface shear rheology
KW - Thermodynamics of adsorption
UR - http://www.scopus.com/inward/record.url?scp=67349234476&partnerID=8YFLogxK
U2 - 10.1016/j.cis.2009.05.002
DO - 10.1016/j.cis.2009.05.002
M3 - Review article
C2 - 19493522
AN - SCOPUS:67349234476
VL - 150
SP - 41
EP - 54
JO - Advances in Colloid and Interface Science
JF - Advances in Colloid and Interface Science
SN - 0001-8686
IS - 1
ER -
ID: 13746316