Authors Müller, M.
Title Orientation of a-Helical Poly(L-lysine) in Consecutively Adsorbed Polyelectrolyte Multilayers on Texturized Silicon Substrates
Date 11.04.2001
Number 9821
Abstract Alternate polyelectrolyte multilayers composed of poly(<FONT SIZE="-1">L</FONT>-lysine) (PLL) in the <IMG SRC="/images/gifchars/alpha.gif" BORDER=0>-helical state and poly(maleic acid-<I>co</I>-<IMG SRC="/images/gifchars/alpha.gif" BORDER=0>-methylstyrene) (PMA-MS) were deposited by consecutively adsorbing from aqueoussolutions on both unmodified and unidirectionally scratched silicon substrates. Thereby, the <IMG SRC="/images/gifchars/alpha.gif" BORDER=0>-helical PLLrods formed in the presence of NaClO<SUB>4</SUB> were found to be significantly aligned along the scratching directionof the substrate. From the dichroic ratios of the amide I and amide II band, obtained by ATR-FTIRspectroscopy, order parameters with respect to uniaxial orientation were determined using a cone distributionmodel and the known angles of the transition dipole moments relative to the helix axis. They ranged from<I>S</I> = 0.5-0.7 for the PLL rods oriented on the texturized Si substrate and <I>S</I> = 0.0-0.2 (<I>S</I> = 1 for perfectordering) for the unoriented PLL rods in the dry and wet states, respectively. Additionally, multilayerscomposed of PLL and poly(vinyl sulfate) showed similar uniaxial alignment on texturized Si substrates (<I>S</I>= 0.6). Generally, drying the multilayers caused a certain loss of order. Surfaces of anisotropically oriented<IMG SRC="/images/gifchars/alpha.gif" BORDER=0>-helical polypeptides could be interesting for biomimetic purposes.
Publisher Biomacromolecules
Citation Biomacromolecules 2 (2001) 262-269

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