Mesoscopic and microscopic investigation on poly(vinyl alcohol) hydrogels in the presence of sodium decylsulfate.
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.
Mangiapia
Gaetano
G
Dipartimento di Chimica, Complesso Universitario di M. S. Angelo, Università degli Studi di Napoli "Federico II", Via Cinthia, 80126 Napoli (NA), Italy.
Ricciardi
Rosa
R
Auriemma
Finizia
F
Rosa
Claudio De
CD
Celso
Fabrizio Lo
FL
Triolo
Roberto
R
Heenan
Richard K
RK
Radulescu
Aurel
A
Tedeschi
Anna Maria
AM
D'Errico
Gerardino
G
Paduano
Luigi
L
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
D020100:Hydrogels; D013451:Sulfonic Acids; D013501:Surface-Active Agents; D011142:Polyvinyl Alcohol; C517619:sodium decylsulfonate