Nataliya Permyakova

Structural Peculiarities of Triblock Copolymers Containing Poly(Ethylene Oxide) and Polyacrylamide

The morphology of the triblock copolymers (TBC) containing chemically complementary poly(ethylene oxide) (M vPEO = 3 · 103 ÷ 1 · 105) and polyacrylamide (M PAAm = 4.5 · 104 ÷ 9.07 · 105) of different chain lengths is studied. The loss of the PEO ability to crystallize in TBC at M vPEO ≤ 4 · 104 is established. At the same time, PEO blocks with M v = 1 · 105 form small crystalline domains in the TBC structure, but their crystallinity degree turns out to be by 2.8 times less than that in individual poly(ethylene oxide). A microphase separation in amorphous regions of the TBC structure at high values of M PAAm is revealed. It is shown that the main reason for the effects observed is the formation of a complex between PEO and PAAm blocks by hydrogen bonds.

Micellar nanocarriers for anticancer drug melanin

ABSTRACT The effective biocompatible and partially biodegradable micellar nanocarriers for encapsulation of the anticancer drug eumelanin were created. Such nanocarries are the products of self-assembly of asymmetric diblock and triblock copolymers, which comprised chemically complementary (methoxy)poly(ethylene oxide) and poly(acrylic acid) blocks of a variable length. A chemical structure and solubility of the eumelanin, the vital activity product of black yeast “Nadsoniella nigra sp. X-1, was characterized. Peculiarities of the micellization process, morphology, size and stability of the developed micellar nanocarries were highlighted. The eumelanin encapsulation into micellar nanocarries with different morphology and a state of the obtained drug/micelle systems were studied and discussed.

Nanostructured Triblock Copolymers with Chemically Complementary Components and their Ionic Conductivity

A series of structural and electrochemical studies of the triblock copolymers (TBCs) based on poly(ethylene oxide) ( M n = 14 and 35 kDa) and polyacrylamide (PAAm- b -PEO- b -PAAm), which formed the intramolecular polycomplexes, were carried out using nuclear magnetic resonance, differential scanning calorimetry, wide-angle and small-angle X-ray scattering, and impedance spectroscopy. The combination of the amorphous mass-fractal-organized structure of the copolymers with high level of the ionic conductivity of pure TBCs and their compositions with the couple KI/I 2 and LiPF 6 salt was established. Possible reasons for the effects in the context of applications of TBC compositions in solar cells and lithium batteries are discussed.

Temperature Effect on Hydrogen Bonds in Triblock Copolymers of Poly(Ethylene Oxide) and Polyacrylamide

The existence and temperature stability of the hydrogen bond system in triblock copolymers based on chemically complementary polyacrylamide and poly(ethylene oxide) are studied. The participation of the trans-multimers of PAA amide groups and oxygen atoms of PEO in the formation of hydrogen bonds between both polymer blocks is established. It is shown that the hydrogen bond system in the copolymers is stable enough in the wide temperature region T = (308 ÷ 473) K. The insignificant destruction of the H-bonds between PAA and PEO blocks and also the cis-trans- and trans-multimers of amide groups in the triblock copolymers is revealed at the temperature increasing.

Micelle Encapsulation of Silver Nanoparticles at Borohydride Reduction

The present work demonstrates the encapsulation of silver nanoparticles into micellar structures of the diblock copolymer (DBC) consisting chemically complementary methoxypoly (ethylene oxide) and poly(acrylic acid). The reduction of silver ions to silver nanoparticles or nanoclusters is achieved by an excess of sodium borohydride in the DBC aqueous solutions with various pH. The formation of considerably more smallest and stable Ag-nanoparticles in the DBC micellar solution at pH = 3 compare with the test of an Ag+solution without DBC micelles was revealed. The morphology of Ag-nanoparticles dispersed within DBC matrices and their average particle size were indicated by TEM images.

Micelle Formation and Stabilization of Metal Nanoparticles in Aqueous Solutions of Diblock Copolymers with Monomethyl Ether of Poly(Ethylene Oxide) and Poly(Acrylic Acid)

Double-hydrophilic block copolymers including monomethyl ether of poly(ethylene oxide) and poly(acrylic acid) (MEPEO-b-PAAc) with the different ratios of polymer blocks are synthesized by the matrix block-copolymerization and characterized. The intramolecular complex formation (IntraPC) between polymer blocks in MEPEO-b-PAAc at low pH (protonated MEPEO-b-PAAc) is established. It causes the MEPEO-b-PAAc intense micellization in aqueous solutions at pH ≤ 4. Water solutions of MEPEO-b-PAAc copolymers are used for the synthesis of silver nanoparticles. The stabilizing property of MEPEO-b-PAAc solutions by the interaction with the colloid dispersions of silver nanoparticles is shown.

Block Copolymers of Methoxypoly(Ethylene Oxide) and Poly(ϵ-Caprolactone): Synthesis, Structure, Micellization, and Interaction with Prednisolon

A series of MOPEO-b-PCL diblock copolymers (DBCs) with M nMOPEO = 2.5 · 103 and M nPCL = (0.28 ÷ 2.43) · 104 was synthesized using the anionic ring-opening block copolymerization. A bulk structure of the copolymers was studied with DSC. One glass transition and three melting peaks for MOPEO-b-PCL were found, thus implying the existence of separate crystalline domains of both blocks in a copolymer structure. The intense micellization of DBCs in dioxane/aqueous solutions was found with a spectrophotometry, a static light scattering, and photography. A reduction in CMC and an increase in −ΔG° values with growth of the PCL length and at the addition of prednisolon (PS) were established. The hydrogen bonding of PS with DBCs was confirmed with FTIR spectroscopy.