In this review, the results of modern theoretical and experimental investigations of three dimen sional reversible deactivation radical polymerization are discussed. The most important factors affecting the critical gelation conversion, the probability of cyclization, and the topological structures of polymers are underlined. Examples of the most promising application of the reversible deactivation radical polymerization to produce new polymer materials are given.

It is shown that branched and highly branched vinyl polymers can be prepared by three dimen sional radical polymerization in the presence of dissolved oxygen, as exemplified by the oxidative copolymer ization of styrene and divinylbenzene. The conditions of synthesis of highly branched polymers with a high yield-the ratio between monovinyl and divinyl comonomers and the rate of oxygen bubbling-are deter mined. The kinetics of formation of branched polystyrenes and the features of their molecular mass distribu tion are studied. Elemental analysis data show that the polymeric product contains 22-24 wt % oxygen, which, according to the IR data, enters into the composition of carbonyl, hydroxyl, and peroxide groups. The thermal decomposition of polymeric products is investigated via the TGA-DSC method. The main exother mal peak at ~145°C is associated with the decomposition of peroxide groups, which is accompanied by the evolution of formaldehyde.

Hydrated copolymers of N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate as a promising platform for biologically active compounds (BAC) were investigated by different physical chemical methods (dynamic light scattering, infrared spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry) and the quantum chemical modeling of water coordination by the copolymers in a solution. According to the quantum chemical simulation, one to two water molecules can coordinate on one O-atom of the lactam ring of VP units in the copolymer. Besides the usual terminal coordination, the water molecule can form bridges to bind two adjacent C=O groups of the lactam rings of VP units. In addition to the first hydration shell, the formation of a second one is also possible due to the chain addition of water molecules, and its structure depends on a mutual orientation of C=O groups. We showed that N,N-dimethylbiguanidine hydrochloride (metformin) as a frontline drug for the treatment of type 2 diabetes mellitus can be associated in aqueous solutions with free and hydrated C=O groups of the lactam rings of VP units in studied copolymers. Based on the characteristics of the H-bonds, we believe that the level of the copolymer hydration does not affect the behavior and biological activity of this drug, but the binding of metformin with the amphiphilic copolymer will delight in the penetration of a hydrophilic drug across a cell membrane to increase its bioavailability.

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