Tatyana Zheltonozhskaya

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.

Micelles of PAAm-b-PEO-b-PAAm Triblock Copolymers and Their Binding with Prednisolon

The IntraPC forming asymmetric PAAm-b-PEO-b-PAAm triblock copolymers (TBCs) composed of poly(ethylene oxide) (M v = 6 · 103 and 1.4 · 104) and polyacrylamide of a variable chain length form “hairy-type” micelles in water and “flower-like” micelles at the addition of EtOH > 40 vol %. The specific micellization is developed in TBC aqueous/ethanol solutions (EtOH content < 30 vol %) at the PS introduction. It is caused by the binding of PS with TBC micelles due to hydrogen bonds and hydrophobic interactions. The amorphous structure of TBCs and polymorphic crystalline structures of PS are found. The products of the interaction of TBC and PS contain highly ordered crystalline structures of the drug. But it is possible to avoid the drug crystallization at low PS contents.

Block-Copolymers of Polyacrylamide with Poly(Ethylene Oxide) Forming Intramolecular Polycomplexes

Diblock-copolymers of polyacrylamide (PAA) and monomethyl ethers of poly(ethylene glycol) (MEPEG) of different molecular weights (M vMEPEG = 7.5 ⋅ 102 − 5 ⋅ 103) are obtained. The positive matrix effect depending on the length of MEPEG chains is revealed. The copolymerization kinetics is measured by dilatometry and compared with that of AA homopolymerization. Molecular parameters of synthesized copolymers are determined by size exclusion chromatography (SEC). Structural investigations are carried out by differential scanning calorimetry (DSC).

Poly(vinyl alcohol)-Graft-Polyacrylamide with Different Grafts Number and Length as Studied by 1H NMR Spectroscopy

ABSTRACT The influence of poly(vinyl alcohol) matrix on stereoregularity of replica polyacrylamide chains in matrix radical graft copolymerization process when varying the grafts number and molecular weight is studied by high-resolution NMR spectroscopy. It was ascertained that the microstructure of formed polymer at homopolymerization and matrix copolymerization processes are not differed. 1H NMR spectroscopy suggests a few contacts of graft chains with the main chain through H-bonding in intramolecular polymer-polymer complex forming in macromolecules of investigated poly(vinyl alcohol)-to-polyacrylamide graft copolymer.

Double Hydrophilic Block Copolymers for Doxorubicin Delivery

The anionic derivative of asymmetric triblock copolymer containing biocompatible chemically complementary polyacrylamide and poly(ethylene oxide) (PAAm-b-PEO-b-PAAm) was obtained. The micellization of the initial (TBC) and modified (TBC-COOH) copolymer samples in aqueous solution were investigated. The similar values of the critical micellization concentration and the Gibbs free micellization energy for initial and modified TBCs were found. The anticancer effects of the doxorubicin (DOX)-loaded micelles of the initial and modified triblock copolymers were studied. The fact of higher efficacy of DOX/TBC and DOX/TBC-COOH compositions in compare with pure DOX was determined and discussed.

The Self-Assembly of Diblock Copolymers MePEG-b-PAAm into Micellar Structures and Their Interaction with Doxorubicin

The micellization of asymmetric diblock copolymers (DBC) MePEG-b-PAAm formed by monomethoxy-poly(ethylene)oxide (MePEG) and polyacrylamide (PAAm) has been studied in water, a water/alcohol mixture, and a NaCl solution. The effect of added NaCl on the critical micellization concentration of DBC water solutions was examined. The interaction between DBC and antitumor drug doxorubicin is discussed. The analysis of the UV spectrum of doxorubicin is performed.

About the compatibility of polymer components in polymer complexes based on poly(acrylamide) and poly(vinyl alcohol)

The issue of applying the usual concepts of polymer compatibility to nonstoichiometric PVA/PAA mixtures of chemically complementary poly(vinyl alcohol) and poly(acrylamide), which form in water solution InterPC (intermolecular polymer complex) stabilyzed by H-bonds, and PAA to PVA graft copolymers (PVA-PAA N ) with different grafted chains number N, that are IntraPC (intramolecular polymer complexes) is discussed. PVA and PAA are compatible on molecular level. At the same time PVA/PAA mixture (50/50 W/W) is characterized by heterogeneous structure consists of InterPC with φ char =9g PVA /g PAA and the excess of unconnected PAA. In the case of IntraPC, yet, only PVA-PAA N , where N=25, is characterized by a single glass transition temperature (Tg). At larger values of N separate PAA domains form giving rise to the corresponding Tg. These results are discussed in view of IntraPC structure peculiarities as a function of N investigated by IR spectroscopy.

Block copolymers containing polyacrylamide and polyacrylic acid: Bulk structure and hydrogen bonds system

ABSTRACT Asymmetric block copolymers PAAc-b-PAAm (DBCs) and PAAm-b-PAAc-b-PAAm (TBCs) comprised poly(acrylic acid) blocks of constant chain length and polyacrylamide blocks of variable chain length were synthesized using RAFT/MADIX technique. Their properties in a bulk state were studied by differential scanning calorimetry and the hydrogen bond system was investigated by Fourier transform infrared spectroscopy. It was found that DBCs and TBCs possess a homogeneous amorphous structure, whose temperatures of glass transition and destruction beginning increased with growth of PAAm block length. The H-bond system between PAAc and PAAm blocks was most developed in TBC sample and formed manly by the mixed cyclic dimmers of carboxyl and amide groups.

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.