Physico-Chemical nanomaterials science

Effect of alkali metals ions on sol-gel transformation in solution of hydroxypropylcellulose

A.O. Sobchuk1, M.M. Lazarenko1, V.I. Kovalchuk1, S.G. Nedilko1, S.V. Gryn2, V.P. Scherbatskyi1, S.Yu. Tkachev1, D.A. Andrusenko1, M.V. Lazarenko3, K.S. Yablochkova1, О.М. Alekseev1

1 Taras Shevchenko National University of Kyiv, Physical Faculty, Volodymyrska St. 64/13, Kyiv 01601, Ukraine. E-mail: litrboychik@gmail.com
2 Taras Shevchenko National University of Kyiv, Institute of High Technologies, Volodymyrs’ka St. 64/13, Kyiv 01601, Ukraine. 
3National University of Food Technologies, Volodymyrs’ka St. 68, Kyiv-01601, Ukraine

The sol-gel transformations in the water solutions of hydroxypropylcellulose (HPC) are widely known, but they still are in field of intensive researches. The peculiarity of these solutions is their ability to change considerably their optical, rheological and other physical properties under influence of different external factors. Considerable scientific interest is caused by demand of modern technologies of the new type of materials, so-called “smart materials”. Physical and chemical properties of “smart materials” can be tuned by changes of certain parameters, such as temperature, pH level, electrical and magnetic fields, etc.
The HPC-water systems could be used as example of the systems of this sort due to formation of aggregates of hydroxypropylcellulose with different size and shape, highly sensitive to temperature, pH and presence of electrolytes. So, addition of electrolytes in HPC-water solutions leads to significant changes in their electrical properties and causes influence on sol-gel transformations.
The aim of the present work is to study the influence of alkali metals ions (IA group) on the physical properties of the solution and sol-gel transformations in the HPC-water solution. The measurements of conductivity, viscosimetry, dynamic light scattering (DLS) method, turbidimetry, absorption and luminescence spectroscopy were used to characterize systems under study.
It was shown that the range of structure transformations shifts to lower temperatures (in the overall range 40..50 oC) in presence of the alkali metals ions (Li+, Na+, K+, Rb+, Cs+). Besides, an formation of bigger particles of polymer was observed.