Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Characterization of the surface free energy of cellulose ether films
Autore:
Luner, PE; Oh, E;
Indirizzi:
Univ Iowa, Coll Pharm, Div Pharmaceut, Iowa City, IA 52242 USA Univ Iowa Iowa City IA USA 52242 Div Pharmaceut, Iowa City, IA 52242 USA
Titolo Testata:
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
fascicolo: 1-3, volume: 181, anno: 2001,
pagine: 31 - 48
SICI:
0927-7757(20010615)181:1-3<31:COTSFE>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONTACT-ANGLE MEASUREMENTS; ACID-BASE PROPERTIES; HYDROXYPROPYL CELLULOSE; POLYMER SURFACES; DRUG-DELIVERY; POLY(METHYL METHACRYLATE); MODELING MUCOADHESION; INTERFACIAL-TENSIONS; LIFSHITZ-VAN; COMPONENTS;
Keywords:
surface free energy; Lifshitz-van der Waals acid-base approach; cellulose ethers; contact angles; work of adhesion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
77
Recensione:
Indirizzi per estratti:
Indirizzo: Luner, PE Yamanouchi Pharm Technol Inc, Stanford Res Pk,1050 Arastradero Rd, Palo Alto, CA 94304 USA Yamanouchi Pharm Technol Inc Stanford Res Pk,1050 Arastradero Rd Palo Alto CA USA 94304
Citazione:
P.E. Luner e E. Oh, "Characterization of the surface free energy of cellulose ether films", COLL SURF A, 181(1-3), 2001, pp. 31-48

Abstract

The objective of this study was to determine the surface free energy components of aqueous-based cellulose ether films and compare these values with those of other cellulose polymers. The surface free energy parameters were calculated from the contact angles of sessile drops of apolar and polar liquids on cellulose ether films cast on glass slides using the Lifshitz-van der Waals/acid-base (LW/AB) approach according to the method of van Oss, Chaudhury and Good. The cellulose ethers studied were hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), hydroxypropyl cellulose (HPC) and hydroxyethyl cellulose (HEC). The total surface free energy of these cellulose ethers ranged from 42 to 50 mJ m(-2) The contribution of the acid-base (AB) component of surface free energy to the total surface free energy of the polymers ranged from 4 to 12%, which was considerably lower than that of cellulose. The cellulose ethers demonstrated near monopolarity and had dominantelectron donor (Lewis-base) character. The overall trend in the values of the thermodynamic terms derived from the surface free energy parameters as indicators of hydrophilicity and hydration were in good agreement with the relative bulk solubility and hydration behavior of the polymers. Independent estimates of the AB character of the polymers from work of adhesion termscalculated from the liquid wetting data agreed with those obtained from the surface free energy parameters. Calculation of the work of adhesion with substrates of varying surface free energy parameters indicated that acid-base interactions made a major contribution to the total work of adhesion between cellulose ethers and bipolar surfaces. Although no direct correlation could be established between the surface free energy parameters and the type of substitution on the cellulose backbone for the cellulose ethers, the values of the terms derived from the LW/AB approach were consistent with those of cellulose and ethylcellulose. The LW/AB approach provides a reasonably consistent method for estimating the surface properties of cellulose ethers and the resulting surface free energy parameters are shown to relate to the interfacial properties of the polymers. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 21:25:32