Transcript Saratov Fall Meeting 2014

Saratov Fall Meeting 2015
Optical activity of chitosan films with
induced anisotropy
Natalia O. Gegel, Anna B. Shipovskaya
Research and Education Institution of Nanostructures and Biosystems,
Saratov State University
Abstract
The optical activity of chitosan films in the form of
polysalt and polybase: the initial ones and those
sorbed formic acid vapor, was studied. The
modification of such films in formic acid vapor is
shown to be accompanied by induced optical
anisotropy, by varying specific optical rotation [α],
and a sign inversion of [α].
Objects of research
The films obtained from the solutions chitosan of formic acid
Research methods
Polarization microscopy
Spectropolarimetry
Experimental scheme
PM films prepared from aqueous formic solution of chitosan,
cycle sorption-desorption vapor 56% formic acid
In the form of polysalts
(S-form)
Molecular weight
of chitosan (CH)
CH-700
CH-200
In the form of polybases
(B-form)
The dependence of the specific optical rotation [α]
of the angle of orientation of the sample θ in polar coordinates
(a)
(b)
Cycle sorption-desorption
vapor 56% formic acid
Original (a) and modified (b) films CH-200
The dependence of the specific optical rotation [α]
of the angle of orientation of the sample θ in polar coordinates
(a)
(b)
Cycle sorption-desorption
vapor 56% formic acid
Original (a) and modified (b) films CH-700
Conclusions
• The optical activity of chitosan in the form of films and polisoli
poliosnovaniya: initial and modified vapor of formic acid;
• The angular dependence (indicatrix) specific optical rotation films, the
orientation angle of the sample relative to the direction of the polarization
vector of the incident light beam in a plane perpendicular to the given beam;
• It is shown that steam treatment results in the formation of films induced
optical anisotropy;
• It is shown that the analyzed systems are characterized by high values ​of
specific optical rotation, indicates the formation of a cholesteric mesophase in
the film by the action of formic acid vapor;
• Indicatrices films modified in pairs of formic acid are irregular.