We study statistical copolymerization effects on the upper critical solution temperature (CST) of generic homopolymers by means of coarse-grained Langevin dynamics computer simulations and mean-field theory. Our systematic investigation reveals that the CST can change monotonically or non-monotonically with copolymerization, as observed in experimental studies, depending on the degree of non-additivity of the monomer (A-B) cross-interactions. The simulation findings are confirmed and qualitatively explained by a combination of a two-component Flory-de Gennes model for polymer collapse and a simple thermodynamic expansion approach. Our findings provide some rationale behind the effects of copolymerization and may be helpful for tuning CST behavior of polymers in soft material design.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Amphiphilic gradient copolymers are promising alternatives to block copolymers for self-assembled nanomaterials due to their straightforward synthesis via statistical copolymerization of monomers with different reactivities and hydrophilicity. By carefully selecting monomers, nanoparticles can be synthesized in a single step through gradient copolymerization-induced self-assembly (gPISA). We synthesized highly sensitive 19F MRI nanotracers via aqueous dispersion gPISA of hydrophilic poly(ethylene glycol) methyl ether methacrylate (PEGMA) with core-forming N,N-(2,2,2-trifluoroethyl)acrylamide (TFEAM). The PPEGMA-grad-PTFEAM nanoparticles were optimized to achieve spherical morphology and exceptional 19F MRI performance. Noncytotoxicity was confirmed in Panc-1 cells. In vitro 19F MR relaxometry and imaging demonstrated their diagnostic imaging potential. Notably, these gradient copolymer nanotracers outperformed block copolymer analogs in 19F MRI performance due to their gradient architecture, enhancing 19F relaxivity. The synthetic versatility and superior 19F MRI performance of gradient copolymers highlight their potential in advanced diagnostic imaging applications.

• MeSH
• hydrofobní a hydrofilní interakce MeSH
• kontrastní látky chemie   chemická syntéza   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• methakryláty * chemie   MeSH
• nádorové buněčné linie MeSH
• nanočástice chemie   MeSH
• polyethylenglykoly * chemie   MeSH
• polymerizace MeSH
• polymery chemie   chemická syntéza   MeSH
• zobrazování fluorovou magnetickou rezonancí metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kontrastní látky MeSH
• methakryláty * MeSH
• polyethylene glycol methacrylate MeSH Prohlížeč
• polyethylenglykoly * MeSH
• polymery MeSH

A new type of vanadium-containing ionic liquids (ILs) was synthesized by cation exchange from barium salts of oxidovanadium(IV) complexes stabilized by edta and its congeners (dcta, oedta, and heedta) serving as pentadentate ligands. All starting barium salts and several magnesium and cesium salts, serving as models for the cation exchange, were structurally characterized by single-crystal XRD analysis. The synthesized ILs consisting of organic cations (Bu4N+, Bmim+, and Bu4P+) and complex anions ([VO(edta)]2-, [VO(dcta)]2-, [VO(oedta)]-, and [VO(heedta)]-) were characterized by analytical and spectroscopic methods including EPR spectroscopy and cyclic voltammetry. Then, ILs were tested as catalysts for the ring-opening copolymerization of epoxy resin with cyclic anhydride showing significant catalytic activity, which led to production of highly cross-linked glassy thermosets. A detailed isothermal DSC kinetic study was performed for the most promising IL showing that the progress of cross-linking can be successfully fitted by the Kamal-Sourour model. Based on the DSC and NIR results, the initiation mechanism of the cross-linking in the presence of vanadium-containing IL was suggested. IL had ability to activate a rapid hydrolysis of anhydride cycle and the formed carboxyl groups initiated a polyesterification. In parallel, the role of imidazolium cation of IL for the initiation of chain-growth anionic copolymerization is also discussed.

• Publikační typ
• časopisecké články MeSH

Polymeric drug carriers exhibit excellent properties that advance drug delivery systems. In particular, carriers based on poly(ethylene oxide)-block-poly(ε-caprolactone) are very useful in pharmacokinetics. In addition to their proven biocompatibility, there are several requirements for the efficacy of the polymeric drug carriers after internalization, e.g., nanoparticle behavior, cellular uptake, the rate of degradation, and cellular localization. The introduction of γ-butyrolactone units into the hydrophobic block enables the tuning of the abovementioned properties over a wide range. In this study, a relatively high content of γ-butyrolactone units with a reasonable yield of ≈60% is achieved by anionic ring-opening copolymerization using 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a very efficient catalyst in the nonpolar environment of toluene with an incorporated γ-butyrolactone content of ≈30%. The content of γ-butyrolactone units can be easily modulated according to the feed ratio of the monomers. This method enables control over the rate of degradation so that when the content of γ-butyrolactone increases, the rate of degradation increases. These findings broaden the application possibilities of polyester-polyether-based nanoparticles for biomedical applications, such as drug delivery systems.

• Klíčová slova
• biodegradation, macrophages, nanomedicine, nanoparticles, γ-butyrolactone,
• MeSH
• buněčná smrt MeSH
• buněčné linie MeSH
• gama-butyrolakton chemická syntéza   chemie   MeSH
• intracelulární prostor metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nanočástice chemie   ultrastruktura   MeSH
• nosiče léků chemie   MeSH
• polyestery chemická syntéza   chemie   MeSH
• polyethylenglykoly chemická syntéza   chemie   MeSH
• polymerizace * MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• viabilita buněk MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• gama-butyrolakton MeSH
• nosiče léků MeSH
• polycaprolactone MeSH Prohlížeč
• polyestery MeSH
• polyethylenglykoly MeSH

In recent years, polymerization-induced self-assembly (PISA) has emerged as a powerful method for the straightforward synthesis of polymer nanoparticles at high concentration. In this study, we describe for the first time the synthesis of poly(2-oxazoline) nanoparticles by dispersion cationic ring-opening polymerization-induced self-assembly (CROPISA) in n-dodecane. Specifically, a n-dodecane-soluble aliphatic poly(2-(3-ethylheptyl)-2-oxazoline) (PEHOx) block was chain-extended with poly(2-phenyl-2-oxazoline) (PPhOx). While the PhOx monomer is soluble in n-dodecane, its polymerization leads to n-dodecane-insoluble PPhOx, which leads to in situ self-assembly of the formed PEHOx-b-PPhOx copolymers. The polymerization kinetics and micellization upon second block formation were studied, and diverse nanoparticle dispersions were prepared, featuring varying block lengths and polymer concentrations, leading to dispersions with distinctive morphologies and physical properties. Finally, we developed a single-step protocol for the synthesis of polymer nanoparticles directly from monomers via gradient copolymerization CROPISA, which exploits the significantly greater reactivity of EHOx compared to that of PhOx during the statistical copolymerization of both monomers. Notably, this approach provides access to formulations with monomer compositions otherwise unattainable through the block copolymerization method. Given the synthetic versatility and application potential of poly(2-oxazolines), the developed CROPISA method can pave the way for advanced nanomaterials with favorable properties as demonstrated by using the obtained nanoparticles for stabilization of Pickering emulsions.

• Klíčová slova
• CROP, Copolymerization, Nanoparticles, PISA, Poly(2-oxazoline)s,
• Publikační typ
• časopisecké články MeSH

In this work, we prepared highly swelling, stimuli-responsive hydrogels capable of the highly efficient adsorption of inorganic pollutants. The hydrogels were based on hydroxypropyl methyl cellulose (HPMC) grafted with acrylamide (AM) and 3-sulfopropyl acrylate (SPA) and were synthesized via the growth (radical polymerization) of the grafted copolymer chains on HPMC, which was activated by radical oxidation. These grafted structures were crosslinked to an infinite network by a small amount of di-vinyl comonomer. HPMC was chosen as a cheap hydrophilic and naturally sourced polymer backbone, while AM and SPA were employed to preferentially bond coordinating and cationic inorganic pollutants, respectively. All the gels displayed a pronounced elastic character, as well as considerably high values of stress at break (several hundred %). The gel with the highest fraction of the ionic comonomer SPA (with an AM/SPA ratio = 0.5) displayed the highest equilibrium swelling ratio (12,100%), the highest volume response to temperature and pH, and the fastest swelling kinetics, but also the lowest modulus. The other gels (with AM/SPA = 1 and 2) displayed several times higher moduli but more modest pH responses and only very modest temperature sensitivity. Cr(VI) adsorption tests indicated that the prepared hydrogels removed this species from water very efficiently: between 90 and 96% in one step. The hydrogels with AM/SPA ratios of 0.5 and 1 appeared to be promising regenerable (via pH) materials for repeated Cr(VI) adsorption.

• Klíčová slova
• Cr(VI) adsorption, cellulose-based hydrogels, graft copolymerization, stimuli-sensitive hydrogels, swelling kinetics,
• Publikační typ
• časopisecké články MeSH

Improving medical implants with functional polymer coatings is an effective way to further improve the level of medical care. Antibacterial and biofilm-preventing properties are particularly desirable in the area of wound healing, since there is a generally high risk of infection, often with a chronic course in the case of biofilm formation. To prevent this we here report a polymeric design of polymer-bound N-acetyl-glucosamine-oligoethylene glycol residues that mimic a cationic, antibacterial, and biocompatible chitosan surface. The combination of easy to use, crosslinkable, thin, potentially 3D-printable polymethacrylate layering with antibacterial and biocompatible functional components will be particularly advantageous in the medical field to support a wide range of implants as well as wound dressings. Different polymers containing a N-acetylglucosamine-methacryloyl residue with oligoethylene glycol linkers and a methacryloyl benzophenone crosslinker were synthesized by free radical polymerization. The functional monomers and corresponding polymers were characterized by 1H, 13C NMR, and infrared (IR) spectroscopy. The polymers showed no cytotoxic or antiadhesive effects on fibroblasts as demonstrated by extract and direct contact cell culture methods. Biofilm formation was reduced by up to 70% and antibacterial growth by 1.2 log, particularly for the 5% GlcNAc-4EG polymer, as observed for Escherichia coli and Staphylococcus aureus as clinically relevant Gram-negative and Gram-positive model pathogens.

• Klíčová slova
• E. coli, MRSA, antibacterial, antibiofilm, biocompatible, carbohydrates, glycosides,
• Publikační typ
• časopisecké články MeSH

After a brief survey of conventional radical polymerization of alkenes, we review their Li(+) catalyzed radical polymerization and their controlled radical polymerization. Emphasis is on homopolymerization, but related copolymerization of less activated monomers is mentioned as well.

• Publikační typ
• časopisecké články MeSH

In situ 1H NMR characterization of copolymerization reactions of various 2-oxazoline monomers at different molar ratios offers detailed insight into the build-up and composition of the polymer chains. Various 2-oxazolines were copolymerized in one single solvent, butyronitrile, with 2-dec-9'-enyl-2-oxazoline, where the double bond allows for post-polymerization modification and can function as a crosslinking unit to form polymer networks. The types of the monomers and their molar ratios in the feed have a strong effect on the microstructure of the forming copolymer chains. Copolymers comprising 2-dec-9'-enyl-2-oxazoline and either 2-ethyl-, 2-isopropyl-, 2-butyl-, 2-heptyl, 2-nonyl- or 2-phenyl-2-oxazoline, show significant differences in sequential structure of copolymers ranging from block to gradient and random ordering of the monomer units. 1H NMR was found to be a powerful tool to uncover detailed oxazoline copolymerization kinetics and evolution of chain composition.

• Publikační typ
• časopisecké články MeSH

Polyelectrolyte microspheres find applications in many fields such as ion exchange columns, fuel cell membranes, and catalysis, to name a few. Synthesis of these microspheres by inverse emulsion polymerization offers various advantages due to the increased specific surface area and high surface charge density. The surface charge density of the obtained polyelectrolyte microspheres is a hundred times higher than that of either particles obtained by dispersion copolymerization of styrene and styrenesulfonic acid or sulfonated microspheres. The morphology, chemical structure, and electro-surface properties of the synthesized microspheres were studied by transmission and scanning electron microscopy, FTIR-spectroscopy, and conductometric and potentiometric titrations, respectively. Using the potentiometric titration it is possible to characterize the structure of the surface layer of polyelectrolyte microspheres as entirely as possible. The study of the ion-exchange capacity of polyelectrolyte microspheres shows that ion-exchange capacity is 2.1 meq g-1 in this case, which is more than 2 times higher than that of sulfonated microspheres, and 20 times higher than that of particles obtained by dispersion copolymerization.

• Publikační typ
• časopisecké články MeSH