H. Kim et Mw. Urban, Reactions of thrombresistant multilayered thin films on poly(vinyl chloride) (PVC) surfaces: A spectroscopic study, LANGMUIR, 14(25), 1998, pp. 7235-7244
These studies focus on the formation of multilayered thrombresistant thin f
ilms containing poly(ethylenimine) (PEI), dextran sulfate (DS), and heparin
(HP), deposited on poly(vinyl chloride) surfaces. Dipping and spin-coating
are employed to deposit multilayers, and using attenuated total reflectanc
e Fourier transform infrared (ATR FT-IR) spectroscopy, the effects of pH, c
oncentration of surface reacting species, and cross-linking conditions on t
he formation of multilayered structures are investigated. Quantitative ATR
FT-IR analysis reveals that, when thin films are deposited by dipping, HP i
s immobilized to form covalent -CH2NH- linkages between PEI-NH2, and termin
al HP-CHO groups. However, when spin-coating is utilized as an application
method, HP takes a parallel orientation, and ionic complexes between PEI-NH
3+(OH-) and HP-SO3-(H3O+) are formed. Quantitative analysis indicates that
the surface concentration of individual layers is significantly lower for s
pin-coated layers.