Photoelectrorheological properties of polyimides with sulfo-acid and sodium salt sulfo-acid groups: a comparative study

The paper describes a new device that allows us to study the effect of ultraviolet irradiation on the electrorheological characteristics of new photosensitive materials based on colloidal polyimide systems containing SO 3 H (PI-I) and SO 3 Na (PI-II) groups. The samples were analyzed using rotational viscometry methods, and a significant effect of irradiation of the systems on the flow velocity and hence the viscosity of the medium and the electrorheological response was shown. At the same time, the dimensional and microrheological properties of colloidal polyimide systems in polar and nonpolar media under simultaneous ultraviolet irradiation and exposure to an electric field were monitored using IR spectroscopy and dynamic light scattering methods. The mobility and zeta potential of polyimide molecules were determined using a sensitive method of phase analysis of light scattering. It is shown that in almost all cases, irradiation of colloidal systems of polyimides led to the uncontrolled formation of larger particles, which decreased during the thermal reaction almost to the initial size, which indicates the stability of the studied systems to external influences (irradiation and electric current). Graphical abstract