title: Mesoscopic and microscopic investigation on poly(vinyl alcohol) hydrogels in the presence of sodium decylsulfate.
abstract: The structure of poly(vinyl alcohol) (PVA) hydrogels formed as a result of freeze/thaw treatments of aqueous solutions of the polymer (11 wt % PVA) in the freshly prepared state is analyzed through the combined use of small (SANS) and ultrasmall (USANS) angle neutron scattering techniques. The structure of these hydrogels may be described in terms of polymer rich regions, with dimensions of the order of 1-2 microm, dispersed in a water rich phase, forming two bicontinuous phases. The PVA chains in the polymer rich phase form a network where the cross-linking points are mainly crystalline aggregates of PVA having average dimensions of approximately 45 A. The structural organization of freeze/thaw PVA hydrogel membranes does not change either after rehydration of dried gels or in the presence of a tensile force. Finally, addition of surfactant micelles inside the gel provides a formulation with both hydrophobic and hydrophilic regions, which demonstrates the potential of the system for drug delivery. Both SANS and EPR measurements show that sodium decylsulfate (C10OS) micelles do not significantly interact with the PVA gel. Variation of the gel structure by the number of freeze/thaw cycles should modulate the rate of release of an active constituent, for example, in a dermal patch.
authors.affiliation: Dipartimento di Chimica, Complesso Universitario di M. S. Angelo, Università degli Studi di Napoli "Federico II", Via Cinthia, 80126 Napoli (NA), Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Mangiapia
authors.forename: Rosa
authors.initials: R
authors.lastname: Ricciardi
authors.forename: Finizia
authors.initials: F
authors.lastname: Auriemma
authors.forename: Claudio De
authors.initials: CD
authors.lastname: Rosa
authors.forename: Fabrizio Lo
authors.initials: FL
authors.lastname: Celso
authors.forename: Roberto
authors.initials: R
authors.lastname: Triolo
authors.forename: Richard K
authors.initials: RK
authors.lastname: Heenan
authors.forename: Aurel
authors.initials: A
authors.lastname: Radulescu
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Tedeschi
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico
authors.forename: Luigi
authors.initials: L
authors.lastname: Paduano
mesh_terms: D001703:Biophysics / Q000379:methods; D002627:Chemistry, Physical / Q000379:methods*; D016503:Drug Delivery Systems; D004578:Electron Spin Resonance Spectroscopy; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D015233:Models, Statistical; D009502:Neutrons; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D012542:Scattering, Radiation; D013314:Stress, Mechanical; D013451:Sulfonic Acids / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D013718:Tensile Strength
chemical_list: D020100:Hydrogels; D013451:Sulfonic Acids; D013501:Surface-Active Agents; D011142:Polyvinyl Alcohol; C517619:sodium decylsulfonate