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In this study, three series of semi-interpenetrating networks were synthesized based on 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), itaconic acid (IA), and poly(vinyl pyrrolidone) (PVP) as interpenetrating polymer. Syntheses were performed by free radical cross-linking/polymerization reaction. The first series represented hydrogels based on 2-hydroxyethyl methacrylate, poly(vinyl pyrrolidone), and itaconic acid, varying of poly(vinyl pyrrolidone) content. The second series of samples were hydrogels based on 2-hydroxyethyl acrylate, poly(vinyl pyrrolidone), and itaconic acid, varying of itaconic acid content. The third series of synthesized samples were based on 2-hydroxyethyl acrylate, poly(vinyl pyrrolidone), and itaconic acid, varying of poly(vinyl pyrrolidone) content. The content of component was varied in order to examine the influence on the structure, pH- and temperature-sensitive swelling-“intelligent” behavior, mechanical properties of hydrogels, as well as antimicrobial and biocompatible potential of hydrogels. Poly(vinyl pyrrolidone) is a linear polymer, which shows satisfactory biocompatibility and hydrophilicity. Itaconic acid gives pH-sensitive-“intelligent” behavior and better hydrophilicity. Hydrogels based on HEMA and HEA show excellent biocompatibility and satisfactory hydrophilicity. All three series of samples showed satisfactory cytocompatibility, as well as the antimicrobial potential tested against most common microbes. The results obtained and presented in this research can contribute to the development of new efficient polymeric biomaterials for biomedical applications.

Atom transfer radical polyaddition (ATRPA) was utilized herein to synthesize a specific functional polyester. We conducted ATRPA of 4-vinylbenzyl 2-bromo-2-phenylacetate (VBBPA) inimer and successfully obtained a linear type poly(VBBPA) (PVBBPA) polyester with benzylic bromides along the backbone. To obtain a novel amphiphilic polymer bottlebrush, however, the lateral ATRP chain extension of PVBBPA with N-vinyl pyrrolidone (NVP) met the problem of quantitative dimerization. By replacing the bromides to xanthate moieties efficiently, we thus observed a pseudo linear first order reversible addition&ndash, fragmentation chain transfer (RAFT) polymerization to obtain novel poly(4-vinylbenzyl-2-phenylacetate)-g-poly(NVP) (PVBPA-g-PNVP) amphiphilic polymer bottlebrushes. The critical micelle concentration (CMC) and particle size of the amphiphilic polymer bottlebrushes were characterized by fluorescence spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM) (CMCs &lt, 0.5 mg/mL, particle sizes = ca. 100 nm). Toward drug delivery application, we examined release profiles using a model drug of Nile red at different pH environments (3, 5, and 7). Eventually, low cytotoxicity and well cell uptake of the Madin-Darby Canine Kidney Epithelial (MDCK) for the polymer bottlebrush micelles were demonstrated.

In this study, we present the synthesis, self-assembly, and enzyme responsive nature of a unique class of well-defined amphiphilic linear-dendritic block copolymers (PNVP-b-dendr(Phe-Lys)n, n = 1&ndash, 3) based on linear poly(N-vinylpyrrolidone) (PNVP) and dendritic phenylalanyl-lysine (Phe-Lys) dipeptides. The copolymers were prepared via a combination ofreversible addition-fragmentation chain transfer (RAFT) /xanthates (MADIX) polymerization of N-vinylpyrrolidone and stepwise peptide chemistry. The results of fluorescence spectroscopy, 1H NMR analyses, transmission electron microscopy (TEM), and particle size analysis demonstrated that the copolymers self-assemble in aqueous solution into micellar nanocontainers that can disassemble and release encapsulated anticancer drug doxorubicin or hydrophobic dye Nile red by trigger of a serine protease trypsin under physiological conditions. The disassembly of the formed micelles and release rates of the drug or dye can be adjusted by changing the generation of dendrons in PNVP-b-dendr(Phe-Lys)n. Furthermore, the cytocompatibility of the copolymers have been confirmed using human lung epithelial cells (BEAS-2B) and human liver cancer cells (SMMC-7721). Due to the fact of their enzyme responsive properties and good biocompatibility, the copolymers may have potential applicability in smart controlled release systems capable of site-specific response.

We report on the preparation of thin conducting films from the poly (N-vinylpyrrolidone) stabilized polyaniline dispersions for the ammonia gas sensor applications. The dispersion is water-based and prepared by means of relatively simple chemical oxidation polymerization of aniline. Two processes were used for the ink deposition, the ink-jet printing and the spray-coating technique. With the former one, the ink was at first tested on the poly (ethylene terephthalate) foil to find a suitable combination of ink formulation and print parameters. After that, the final ammonia gas sensors were fabricated by both deposition techniques and compared. The aspects of the ink preparation and alteration, as well as the active layer properties, are analyzed by means of UV-vis spectroscopy, optical microscopy, atomic force microscopy, profilometry and electrical measurements. The results obtained from each deposition technique are discussed. In both cases, the sensitivity to the ammonia gas has been demonstrated, making the proposed ink in combination with the two named deposition processes feasible for the potential large-area sensor production.

A mini-library of star-shaped thermoresponsive polymers having six arms was prepared using a hexafunctional xanthate by reversible addition–fragmentation chain transfer (RAFT) polymerization. Star polymers with homopolymeric arms of poly(N-vinylcaprolactam) (PNVCL), copolymeric arms of poly(N-vinylcaprolactam-co-N-vinylpyrrolidone) (PNVCL-co-PNVP) and also arms of block copolymers of PNVCL-b-PVAc, (PNVCL-co-PNVP)-b-PVAc, and combinations of them changing the order of the block was achieved exploiting the R-RAFT synthetic methodology (or R-group approach), wherein the thiocarbonyl group is transferred to the polymeric chain end. Taking advantage of the RAFT benefits, the molecular weight of the star polymers was controlled (Mn = 11,880–153,400 g/mol) to yield star polymers of different sizes and lower critical solution temperature (LCST) values. Removing the xanthate group of the star polymers allowed for the introduction of specific functional groups at the ends of the star arms and resulted in an increase of the LCST values. Star PNVCL-b-PVAc diblock copolymers with PVAc contents of 5–26 mol % were prepared; the hydrophobic segment (PVAc) is located at the end of the star arms. Interestingly, when the PVAc content was 5–7 mol %, the hydrodynamic diameter (Dh) value of the aggregates formed in water was almost the same sa the Dh of the corresponding PNVCL star homopolymers. It is proposed that these star block copolymers self-assemble into single flowerlike micelles, showing great stability in aqueous solution. Star block copolymers with the PVAc hydrophobic block in the core of the star, such as PVAc-b-(PNVCL-co-PNVP), form micellar aggregates in aqueous solution with Dh values in the range from ~115 to 245 nm while maintaining a thermoresponsive behavior. Micellar aggregates of selected star polymers were used to encapsulate methotrexate (MTX) showing their potential in the temperature controlled release of this antineoplasic drug. The importance of the order in which each block constituent is introduced in the arms of the star polymers for their solution/aggregation behavior is demonstrated.

Through the reversible addition–fragmentation chain transfer (RAFT) copolymerization of 3-ethyl-1-vinyl-2-pyrrolidone (C2NVP) and N-vinylpyrrolidone (NVP), a series of well-defined P(C2NVP-co-NVP) copolymers were synthesized (Mn = ca. 8000 to 16,000 and Mw/Mn