Nanocomposites and nanomaterials

Influence of structure and nature of pseudopolyamino acids on size and morphology of their particle in self-stabilized aqueous dispersions
Stasiuk A.V. 1, Fihurka N. V. 1, Prychak S.P. 1, Ostapiv D.D. 2, Varvarenko S.M. 1, Samaryk V.Y. 1
1 Department of Organic Chemistry Lviv Polytechnic National University
S.Bandera Str., 12, Lviv-79013, Ukraine
E-mail: anna.v.stasiuk@lpnu.ua
2 Institute of Animal Biology, NAAS of Ukraine, Lviv, Ukraine
V. Stusa Str., 38, Lviv-79034, Ukraine

The creation of the latest nanocarriers for drug delivery is an urgent task of the modern pharmaceutical industry. Amphiphilic polymers are now attracting the greatest attention of scientists to create drug delivery systems. The surface-active properties of amphiphilic polymers describe their ability to stabilize the dispersed phases of colloidal solutions or to form particles of colloidal size due to self-stabilization. These studies have led to the development of micellar carriers with solubilized drugs that can be safely administered to the human body.
The design of lyophilic and hydrophilic sites of the macromolecule has the most significant influence on surface activity. The studies show a clear relationship between the composition and structure of these areas and the surface activity and ability to form self-stabilizing particles of the dispersed phase in aqueous media. The surface tension isotherms of aqueous polymer dispersions are characterized by two inflection (CCM and CCA). At concentrations lower than the CCM, a monomodal particle size distribution with an average diameter of 25–30 nm is observed, corresponding to the sizes of the associates of individual macromolecules. The size of the primary micelles of polymer particles, which are formed in the range of concentrations close to CCM, is 70-140 nm. At polymer concentrations in a solution close to CCA, rearrangement of primary polymer particles into aggregates with an average size of 320 ÷ 450 nm is observed, and further aggregation of aggregates is observed to micellar formations of even larger size. 
The obtained experimental data using physicochemical methods of analysis confirm the orderly organization of the dispersed phase of pseudopolyamino acids in their aqueous solutions and allow to describe the features of their morphological transformations with the method of production and composition.