IMBICE   05372
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA CELULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Functionalization of nanochannels by grafting polymerization on PET track-etched membranes
Autor/es:
S.L. SOTO ESPINOZA, C. R. ARBEITMAN, M.C. CLOCHARD, AND M. GRASSELLI.
Lugar:
Cracow.
Reunión:
Simposio; 10th Meeting of the Ionizing Radiation and Polymers Symposium. IRaP 2012; 2012
Resumen:
Track-etched membranes are a special kind of membranes
were pores are build ?one per one? by swift-heavy ions bombardment onto
polymeric films. Latent tracks made by particle bombardment are subsequent
etched with specific chemical reagents according to the chemical structure of the
trunk polymer. Unique properties of these membranes, very narrow pore size
distribution and controlled pore number per area have specific applications in
biology area. Track-etched membranes are currently commercial products useful
for cell separation and air monitoring, cell biology, and liposome preparation
by lipid extrusion. Novel application to nanotechnology such us to prepare
nanowires, nanofilters and sensors for special usage has been reviewed [1]. In
addition, single-ion nanochannels and nanowires fabrication are currently
possible [2].
In the progress of the chemical etching the damaged
region is dissolved by hydrolyzing polymer chains, reaching pore diameters in
the range of nano to micrometer scale. After etching procedure on irradiated
polymer still there are enough active sites left that can be used to initiate a
polymerization process. In this way, grafting polymerization in the track pores
can be performed selectively. Acrylic acid has been polymerized onto the pore
wall of track-etched membranes of polypropylene and PVDF [3,4].
In this work track-etched polyethylene terephalate
(PET) membrane has been grafted onto nanopore walls with the reactive glycildyl
methacrylate (GMA) monomer. To visualize the grafting yield we used very
sensitive techniques such as Field Emission SEM (FESEM) and fluorescent methods.
Grafting was performed with 10% GMA solution at 62 C under nitrogen atmosphere
in the range of 15 min to 24 h. Epoxy
groups from grafted polyGMA were revealed by covalent link to fluorescein and
measured directly by the spectrofluorometer Nanodrop® 3300. Fluorescent
relative units (RFU) increase up to four hours of grafting time. This result
was also confirmed by fluorescence microscopy and confocal microscopy where
fluorescence signals were restricted to the pore region. Using a PET foil with
the same ion fluence, we found a direct correlation between RFU and pore
diameter between 50 and 540 nm. Taking into account a functional membrane
property, a reduction in permeability of grafted membranes was analyzed by
molecular diffusion of fluorescent probes.
References
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Mitchell, M. Farmer, P.J.F. Harris (2009); Radiat.
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R. Spohr, C. Zet, B. E. Fischer, H. Kiesewetter, P. Apel,
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NIMBS B 268, 676.
3.
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(2007); NIMBS B 265, 309.
4.
R. Mazzei, G. García Bermúdez, V.C. Chappa, M.F. del
Grosso, A. Fernandez (2006); NIMBS B 251,
99.