Applications of SR-XRF to Characterize Biogels Obtained by Irradiation of Aqueous Biopolymers Solutions

PEREZ R.D., RUBIO M., PEREZ C.A., AUSAR F., BELTRAMO D., GERMANIER A., BIANCO I.

RADIATION PHYSICS AND CHEMISTRY (OXFORD)

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2004 vol. 71 p. 999 - 1000

0969-806X

During the radiation of aquous solutions of polymers with X-rays, chemical reactions are produced by means of reactive species such as hydrated electrons, hydroxyl radicals and hydrogen atoms. Intermolecular crosslinking reactions results in linking polymers chains; thus they lead to the formation of macroscopic hydrogels. Two additional advantages are obtained when radiation is used to form hydrogels: sterilization and "permanent" covalently crosslinked networks. The goals of this study are first a new methodology to determine the diffusion coefficient  of  low atomic weight molecules in radiation-formed hydrogels. In so-doing, a high degree of collimation of the synchrotron beam is used. Second is the direct measurment, by grazing exit (GE) XRF, of the polymer concentration profile near the air-gel interface, being otherwise generally not easily accesible by experiments. It is known that due to the strong interaction of the polymer in aqueous solutions, an enhanced concentration layer(of thickness tens up to hundreds of A) is formed at the surface. Our results show tha the following its formation, the existence of this layer persist as a stable entity over weeks