Self-organized meso- and hybridic phases of poly(aspartic acid) and poly(glutamic amino acid) with cationic surfactants (C(n)TAB, n=14, 16) and a silica source (TEOS)

 
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Self-organized meso- and hybridic phases of poly(aspartic acid) and poly(glutamic amino acid) with cationic surfactants (C(n)TAB, n=14, 16) and a silica source (TEOS) (EN)

Kodona, E. K. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Kodona, E. K. (EN)

In this work the self-organized mesophases obtained by the ionic interaction of poly( amino acids) poly(L-aspartic acid (P-L-Asp) and poly(L-glutamic acid) (P-L-Glu) with the cationic surfactants C(14)TAB and C(16)TAB, as well as the mesoporous silicate materials obtained by addition and hydrolysis of tetraethyl orthosilicate ( TEOS) on the hybridic mesophases, are described. The mesophases isolated at pH 6.5-8.5 were examined by X-ray diffraction (XRD) analysis for their structure, thermogravimetry for their thermal stability, scanning electron microscopy for their structural features, and circular dichroism (CD) for the conformation of the polypeptide-C(n)TAB (n = 14, 16) complexes. The mesophases P-L-Asp/C(14)TAB isolated at pH 7.5 and 8.5 showed in XRD a single peak at d = 3.45 nm and d = 3.54 nm, respectively, corresponding to typical hexagonal packing of the micellar aggregates. The mesophases P-L-Asp/C(16)TAB isolated at pH 7.5 showed an XRD peak at d = 3.90 nm, corresponding to a similar hexagonal packing of larger micellar aggregates and also two peaks at d = 3.37 nm and d = 1.69 nm indicating a layered configuration of the micellar sheets. The layered component decreases by the increase of pH from 7.5 to 8.5 or the addition of small amounts (0.5%) of EtOH. The P-L-Glu/C(14)TAB mesophases isolated at pH 7.5 and 8.5 showed a single XRD peak at d = 3.60 nm, while the P-L-Glu/C(16)TAB system showed also a single XRD peak at d = 4.10 nm. The CD spectra showed that the complexes P-L-Asp/ C(14)TAB possess a more random configuration compared to the P-L-Glu/C(14)TAB, which have the tendency to form alpha- and 3(10)-helices. The mesoporous silicate materials obtained from the systems P-L-Asp/C(16)TAB/ TEOS and P-L-Glu/C(16)TAB/ TEOS showed a single XRD peak corresponding to hexagonal pore arrangement typical in MCM-41 materials. The nitrogen adsorption-desorption isotherms of the silicate mesostructures indicate that they possess high surface areas in the range 500-800 m(2) g(-1) for the P-L-Asp/ C(n)TAB/TEOS and 1000-1070 m(2) g(-1) for the P-L-Glu/C(n)TAB/ TEOS and ordered or semi-ordered porosity depending on the hybridic system used for isolating the corresponding mesophases. (EN)

sodium dextran sulfate (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Chemistry of Materials (EN)

Αγγλική γλώσσα

2007

<Go to ISI>://000245208100043

American Chemical Society (EN)



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