The thermo-sensitive phase transition behavior of linear copolymers based on N-isopropylacrylamide and
acrylamide (poly(NIPAAm-co-AAm)) has been studied by means of ATR - FTIR spectroscopy. The investigations were
carried out in aqueous solution or different phosphate buffer systems (pH = 7.4). The variables here were the comonomer
ratio in the copolymers, the copolymer concentration in the solution and the ionic strength of the solvent.
Increasing the ratio of AAm in the final copolymer composition produced a large shifting of the lower critical transition
temperature (LCST) towards higher values, as a well as a broadening of the phase transition domain, regardless the
solvent type.
The electronic absorption spectra of four carbanion monosubstituted pyridazinium ylids in binary solvents are
analyzed in this paper. The binary solvent is made, in different ratios, by two miscible liquids (one active and one
inactive from the intermolecular interactions point of view). The composition of the first solvation shell of the studied
ylids was established by using the spectral data. The concentration of the active solvent in the first solvation shell is
higher than in the rest of the ternary solution. The difference is appreciable especially at low molar concentrations of the
active solvent in ternary solutions. The interaction energy in pairs of pyridazinium ylid-active solvent molecules was also
estimated in the limits of a cell model of the ternary solution.
Variable - angle ATR-FTIR spectroscopy was applied to the evaluation of the in-depth homogeneity of
amidation within superficial layers of poly(ethylene terephthalate) (PET) surfaces. Thin films of PET were subjected to
aminolysis with triethylenetetramine and tetraethylenepentamine by wet chemistry and using air plasma as precursor,
respectively, in order to create surface functionalities. By varying the incidence angle of the infrared radiation, chemical
changes were investigated from layers of different thicknesses. The amide II band has been selected as a marker for
monitoring the aminolysis products and for depth profiling. The choice of an exponential decay of the in-depth amide
distribution was justified by the quite regular decreasing of the angular absorbance with depth of penetration of the
evanescent wave.
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