http://www.cnr.it/ontology/cnr/individuo/prodotto/ID54754
Influence of the Structural Properties of Poly(vinylidene fluoride) Membranes on the Heterogeneous Nucleation Rate of Protein Crystals (Articolo in rivista)
- Type
- Label
- Influence of the Structural Properties of Poly(vinylidene fluoride) Membranes on the Heterogeneous Nucleation Rate of Protein Crystals (Articolo in rivista) (literal)
- Anno
- 2006-01-01T00:00:00+01:00 (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
- 10.1021/jp061531y (literal)
- Alternative label
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Curcio E.; Fontananova E.; Di Profio G.; Drioli E. (literal)
- Pagina inizio
- Pagina fine
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
- Rivista
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- Note
- ISI Web of Science (WOS) (literal)
- Scopus (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- Università della Calabria, Dip. Ingegneria Chimica e dei Materiali
Istituto per la Tecnologia delle Membrane ITM-CNR (literal)
- Titolo
- Influence of the Structural Properties of Poly(vinylidene fluoride) Membranes on the Heterogeneous Nucleation Rate of Protein Crystals (literal)
- Abstract
- In this study, the influence of the morphological parameters of microporous poly(vinylidene fluoride) (PVDF)
membranes on the heterogeneous nucleation rate of hen egg white lysozyme (HEWL) crystals has been
investigated. Experiments have been carried out on membranes prepared by non-solvent-induced phase inversion
method, using PVDF-co-hexafluoropropylene (Kynarflex 2800) and PVDF homopolymer (Kinar 460), and
adding LiCl and poly(vinylpyrrolidone) (PVP) in order to modulate the pore structure. From a theoretical
point of view, the free Gibbs energy balance for the formation of a critical nucleus has been adapted to
nonporous surfaces, thus obtaining a mathematical correlation between the energy nucleation barrier, the
membrane porosity, and the contact angle between protein solution and polymeric substrate. The energetic
barrier to heterogeneous nucleation was found to increase at higher contact anglessaccording to the prediction
of classical theorysand to decrease at higher porosity. For instance, the predicted ¢Ghet/¢Ghom ratio for
PVDF-Kynarflex (PVP 2.5%) membrane with porosity of 0.11 was 0.30, 35% lower with respect to the
value calculated by the Volmer equation for a dense polymeric matrix having the same contact angle (87.4
( 5.8°). In addition, the effect of the membrane pore size, porosity, and thickness on the removal rate of
solvent have been discussed. For example, the transmembrane flux through PVDF-Kynar (LiCl 5.0%)
membrane was 12% inferior than the one measured under the same experimental conditions through PVDFKynarflex
(LiCl 7.5%) membrane, the latter having similar pore size and thickness but higher porosity (0.44
vs 0.32). The possibility to achieve rapidly a high level of supersaturation is expected to increase the nucleation
rate. In general, measurements performed during crystallization tests carried out at pH 4.5 in NaAc 0.05 M
buffer with different precipitant (NaCl) concentrations agree with the predicted trends. (literal)
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