Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface

Surface pressure isotherms and structural and surface dilatational properties of three hydroxypropylmethycelluloses (HPMCs, called E4M, E50LV, and F4M) adsorbed films at the air-water interface were determined. In this work we present evidence that HPMC molecules are able to diffuse and saturate the...

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Autores principales:	Pérez, Oscar E., Pilosof, Ana María Renata
Publicado:	2006
Materias:	Cellulose films Elastic moduli Isotherms Molecular weight Molecules Rheology Thermodynamic properties Viscoelasticity Elastic dilatational modulus Molecular level Surface pressure isotherms Cellulose adsorbent hydroxypropylmethylcellulose methyl group water air article chemical structure concentration (parameters) controlled study diffusion elasticity film hypobarism interface pressure isotherm molecular dynamics molecular weight phase transition priority journal substitution reaction surface property thermodynamics viscoelasticity Air Elasticity Methylcellulose Phase Transition Thermodynamics Water Cellulose Film Elastic Strength Hydroxypropyl Methyl Cellulose Molecular Weight Thermal Properties
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15257797_v7_n1_p388_Perez http://hdl.handle.net/20.500.12110/paper_15257797_v7_n1_p388_Perez
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_15257797_v7_n1_p388_Perez
record_format	dspace
spelling	paper:paper_15257797_v7_n1_p388_Perez2025-07-30T18:55:16Z Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface Pérez, Oscar E. Pilosof, Ana María Renata Cellulose films Elastic moduli Isotherms Molecular weight Molecules Rheology Thermodynamic properties Viscoelasticity Elastic dilatational modulus Molecular level Surface pressure isotherms Cellulose adsorbent hydroxypropylmethylcellulose methyl group water air article chemical structure concentration (parameters) controlled study diffusion elasticity film hypobarism interface pressure isotherm molecular dynamics molecular weight phase transition priority journal substitution reaction surface property thermodynamics viscoelasticity Air Elasticity Methylcellulose Phase Transition Thermodynamics Water Cellulose Film Elastic Strength Hydroxypropyl Methyl Cellulose Isotherms Molecular Weight Molecules Rheology Thermal Properties Viscoelasticity Surface pressure isotherms and structural and surface dilatational properties of three hydroxypropylmethycelluloses (HPMCs, called E4M, E50LV, and F4M) adsorbed films at the air-water interface were determined. In this work we present evidence that HPMC molecules are able to diffuse and saturate the air-water interface at very low concentrations in the bulk phase. As bulk concentration increased, structural changes at a molecular level occurred at the interface. These changes corresponded to transition from an expanded structure (structure I) to a condensed one (structure II). When the surface concentration of HPMC was high enough, the collapse of the monolayer was observed. The three HPMCs formed very elastic films at the air-water interface, even at low surface pressures. E4M showed features that make it unique. For instance it showed the highest surface activity, mainly at low bulk concentrations (<10-4 wt %). The differences observed in surface activity may be attributed to differences in the hydroxypropyl molar substitution and molecular weight of HPMC. All three HPMCs formed films of similar viscoelasticity and elastic dilatational modulus, which can be accounted for by their similar degree of methyl substitution. © 2006 American Chemical Society. Fil:Pérez, O.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Pilosof, A.M.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2006 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15257797_v7_n1_p388_Perez http://hdl.handle.net/20.500.12110/paper_15257797_v7_n1_p388_Perez
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Cellulose films Elastic moduli Isotherms Molecular weight Molecules Rheology Thermodynamic properties Viscoelasticity Elastic dilatational modulus Molecular level Surface pressure isotherms Cellulose adsorbent hydroxypropylmethylcellulose methyl group water air article chemical structure concentration (parameters) controlled study diffusion elasticity film hypobarism interface pressure isotherm molecular dynamics molecular weight phase transition priority journal substitution reaction surface property thermodynamics viscoelasticity Air Elasticity Methylcellulose Phase Transition Thermodynamics Water Cellulose Film Elastic Strength Hydroxypropyl Methyl Cellulose Isotherms Molecular Weight Molecules Rheology Thermal Properties Viscoelasticity
spellingShingle	Cellulose films Elastic moduli Isotherms Molecular weight Molecules Rheology Thermodynamic properties Viscoelasticity Elastic dilatational modulus Molecular level Surface pressure isotherms Cellulose adsorbent hydroxypropylmethylcellulose methyl group water air article chemical structure concentration (parameters) controlled study diffusion elasticity film hypobarism interface pressure isotherm molecular dynamics molecular weight phase transition priority journal substitution reaction surface property thermodynamics viscoelasticity Air Elasticity Methylcellulose Phase Transition Thermodynamics Water Cellulose Film Elastic Strength Hydroxypropyl Methyl Cellulose Isotherms Molecular Weight Molecules Rheology Thermal Properties Viscoelasticity Pérez, Oscar E. Pilosof, Ana María Renata Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
topic_facet	Cellulose films Elastic moduli Isotherms Molecular weight Molecules Rheology Thermodynamic properties Viscoelasticity Elastic dilatational modulus Molecular level Surface pressure isotherms Cellulose adsorbent hydroxypropylmethylcellulose methyl group water air article chemical structure concentration (parameters) controlled study diffusion elasticity film hypobarism interface pressure isotherm molecular dynamics molecular weight phase transition priority journal substitution reaction surface property thermodynamics viscoelasticity Air Elasticity Methylcellulose Phase Transition Thermodynamics Water Cellulose Film Elastic Strength Hydroxypropyl Methyl Cellulose Isotherms Molecular Weight Molecules Rheology Thermal Properties Viscoelasticity
description	Surface pressure isotherms and structural and surface dilatational properties of three hydroxypropylmethycelluloses (HPMCs, called E4M, E50LV, and F4M) adsorbed films at the air-water interface were determined. In this work we present evidence that HPMC molecules are able to diffuse and saturate the air-water interface at very low concentrations in the bulk phase. As bulk concentration increased, structural changes at a molecular level occurred at the interface. These changes corresponded to transition from an expanded structure (structure I) to a condensed one (structure II). When the surface concentration of HPMC was high enough, the collapse of the monolayer was observed. The three HPMCs formed very elastic films at the air-water interface, even at low surface pressures. E4M showed features that make it unique. For instance it showed the highest surface activity, mainly at low bulk concentrations (<10-4 wt %). The differences observed in surface activity may be attributed to differences in the hydroxypropyl molar substitution and molecular weight of HPMC. All three HPMCs formed films of similar viscoelasticity and elastic dilatational modulus, which can be accounted for by their similar degree of methyl substitution. © 2006 American Chemical Society.
author	Pérez, Oscar E. Pilosof, Ana María Renata
author_facet	Pérez, Oscar E. Pilosof, Ana María Renata
author_sort	Pérez, Oscar E.
title	Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
title_short	Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
title_full	Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
title_fullStr	Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
title_full_unstemmed	Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
title_sort	thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface
publishDate	2006
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15257797_v7_n1_p388_Perez http://hdl.handle.net/20.500.12110/paper_15257797_v7_n1_p388_Perez
work_keys_str_mv	AT perezoscare thermodynamicanddynamiccharacteristicsofhydroxypropylmethylcelluloseadsorbedfilmsattheairwaterinterface AT pilosofanamariarenata thermodynamicanddynamiccharacteristicsofhydroxypropylmethylcelluloseadsorbedfilmsattheairwaterinterface
_version_	1840323486515462144

Thermodynamic and dynamic characteristics of hydroxypropylmethylcellulose adsorbed films at the air-water interface

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