Precipitation Polymerization: A Powerful Tool for Preparation of Uniform Polymer Particles

Photo-induced synthesis of polymeric nanoparticles and chemiluminescent degradable materials via flow chemistry

We report the photo-induced, additive-free, continuous synthesis of polymeric particles using flow chemistry. Not only can these particles be formed under ambient conditions in a solely light-induced precipitation polymerisation, they can be prepared via continuous flow techniques to up-scale the synthetic process. We carefully assess the flow chemical parameters and analyse the resulting particles quantitatively using scanning electron microscopy (SEM). Particle formation is a direct result of the step-growth polymerisation via a photochemically induced AA + BB Diels-Alder reaction, which we herein base on the dialdehyde monomer (AA) derived from the sustainable precursor, thymol. By employing a peroxyoxalate bismaleimide (BB), we introduce particles that can be selectively degraded on-demand, self-reported by light emission through chemiluminescence.

Morphology and size control of an amorphous conjugated polymer network containing quinone and pyrrole moieties via precipitation polymerization

Morphology and size control of insoluble and infusible conjugated polymers are significant for their applications. Development of a precipitation polymerization route without using a surface stabilizer is preferred to control the reaction, morphology, and size. In the present work, precipitation polymerization for an amorphous conjugated polymer network, a new type of polymerized structure containing functional units, was studied for the size and morphology control in the solution phase at low temperature. The random copolymerization of benzoquinone (BQ) and pyrrole (Py) monomers formed microspheres of the BQ-Py network polymers as the precipitates in the solution phase. The particle diameter was controlled in the range of 70 nm and 1 μm by changing the pH of the solution and concentration of the monomers. The resultant nanoparticles were applied to a metal-free electrocatalyst for the hydrogen evolution reaction (HER). The catalytic activity of the BQ-Py nanoparticles was higher than that of the bulk micrometer-sized particles. The results imply that the morphology and size of amorphous conjugated polymer networks can be controlled by precipitation polymerization.

Enhancing the optical properties of [P(MMA-co-AN)/ZrO2]TF by doping fluorescein dye, TD-DFT/DMOl3 simulations and COVID-19 main protease docking

Poly methyl methacrylate-co-acrylonitrile [P(MMA-co-AN)]HB hybrid blend was first synthesized by precipitation polymerization and characterized by static light scattering. With a thickness of 200 ± 5 nm, the hybrid nanocomposite of [P(MMA-co-AN)/ZrO2]HNC thin films were fabricated by spin coating method. X-Ray diffraction studies showed a monoclinic cell structure with an average crystalline size of 180 nm for the fabricated films. An improvement in the optical properties were figured out when fluorescein dye was doped in the hybrid nanocomposite. Where the optical energy gap was decreased from 4.31 to 4.025 eV for fluorescein doped hybrid nanocomposite. While a possible energy transfer between ZrO2 and fluorescein was investigated in the laser photoluminescence spectra. DFT-CASTEP simulations were deployed to calculate the theoretical optical properties for the molecules under consideration. The structural and optical simulations of [P(MMA-co-AN)/ZrO2]HNC were found to match the experimental data. Molecular docking studies of [P(MMA-co-AN)/ZrO2]Iso against the main protease of novel corona virus COVID 19 (PDB code 6LU7 Hormone) showed an interesting interaction.

Advances in Nanohybrid Membranes for Dye Reduction: A Comprehensive Review

Separating valuable materials such as dyes from wastewater using membranes and returning them to the production line is a desirable environmental and economical procedure. However, sometimes, besides filtration, adsorption, and separation processes, pollutant destruction also can be suitable using photocatalytic membranes. The art of producing nanohybrid materials in contrast with nanocomposites encompasses nanomaterial synthesis as a new product with different properties from raw materials for nanohybrids versus the composition of nanomaterials for nanocomposites. According to the findings of this research, confirming proper synthesis of nanohybrid is one challenge that can be overcome by different analyses, other researchers' reports, and the theoretical assessment of physical or chemical reactions. The application of organic-inorganic nanomaterials and frameworks is another challenge that is discussed in the present work. According to the findings, Nanohybrid Membranes (NHMs) can achieve 100% decolorization, but cannot eliminate salts and dyes, although the removal efficiency is notable for some salts, especially divalent salts. Hydrophilicity, antifouling properties, flux, pressure, costs, usage frequency, and mechanical, chemical, and thermal stabilities of NHMs should be considered.

Development of ionic liquid-coated PLGA nanoparticles for applications in intravenous drug delivery

Polymeric nanoparticles (NPs) are a promising platform for medical applications in drug delivery. However, their use as drug carriers is limited by biological (e.g., immunological) barriers after intravenous administration. Ionic liquids (ILs), formed from bulky asymmetric cations and anions, have a wide variety of physical internal and external interfacing properties. When assembled on polymeric NPs as biomaterial coatings, these external-interfacing properties can be tuned to extend their circulation half-life when intravenously injected, as well as drive biodistribution to sites of interest for selective organ accumulation. In our work, we are particularly interested in optimizing IL coatings to enable red blood cell hitchhiking in whole blood. In this protocol, we describe the preparation and physicochemical and biological characterization of choline carboxylate IL-coated polymeric NPs. The procedure is divided into five stages: (1) synthesis and characterization of choline-based ILs (1 week); (2) bare poly(lactic-co-glycolic acid) (50:50, acid terminated) Resomer 504H (PLGA) NP assembly, modified from previously established protocols, with dye encapsulation (7 h); (3) modification of the bare particles with IL coating (3 h); (4) physicochemical characterization of both PLGA and IL-PLGA NPs by dynamic light scattering, 1H nuclear magnetic resonance spectroscopy, and transmission electron microscopy (1 week); (5) ex vivo evaluation of intravenous biocompatibility (including serum-protein resistance and hemolysis) and red blood cell hitchhiking in whole BALB/c mouse blood via fluorescence-activated cell sorting (1 week). With practice and technique refinement, this protocol is accessible to late-stage graduate students and early-stage postdoctoral scientists.

Functional Nanogel from Natural Substances for Delivery of Doxorubicin

Nanogels (NGs) have attracted great attention because of their outstanding biocompatibility, biodegradability, very low toxicity, flexibility, and softness. NGs are characterized with a low and nonspecific interaction with blood proteins, meaning that they do not induce any immunological responses in the body. Due to these properties, NGs are considered promising candidates for pharmaceutical and biomedical application. In this work, we introduce the development of novel functional nanogel obtained from two naturally based products—citric acid (CA) and pentane-1,2,5-triol (PT). The nanogel was synthesized by precipitation esterification reaction of CA and PT in tetrahydrofuran using N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC) and 4-(dimethylamino)pyridine (DMAP) catalyst system. Dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM) analyses revealed formation of spherical nanogel particles with a negative surface charge. Next, the nanogel was loaded with doxorubicin hydrochloride (DOX) by electrostatic interactions between carboxylic groups present in the nanogel and amino groups of DOX. The drug-loaded nanogel exhibited high encapsulation efficiency (EE~95%), and a bi-phasic release behavior. Embedding DOX into nanogel also stabilized the drug against photodegradation. The degradability of nanogel under acidic and neutral conditions with time was investigated as well.

Superhydrophobic fluorinated microspheres for fluorous affinity chromatography

Fluorous affinity chromatography has received growing attention in separation and purification of fluoro compounds, but the wettability of the fluorinated stationary phases is seldom noticed. Here, we construct a series of micro-sized fluorine-containing microspheres by solvothermal precipitation polymerization. The fluorinated microspheres could be obtained with narrow size distribution at even high monomer loading of 15 wt%. Through alternating fluoro monomer, both the particle size and the wettability of the microsphere array could be tuned. Among them, the poly(divinylbenzene -dodecafluoroheptyl methacrylate), P(DVB-DFHMA), microsphere (6.1 μm) arrays displays superhydrophobicity with 153.2° water contact angle. The P(DVB-DFHMA) fluorinated microspheres (7.58% fluorine content) can be packed into steel-less columns as stationary phase for high-performance liquid chromatography. The retention mechanism of the fluorinated column is proven to be the specific fluorine-fluorine interaction. Compared to the commercial C18 silica column, the fluorinated column can completely separate fluorine-containing compounds under high water content mobile phase, including small fluoro molecules and fluoro macromolecules, at much lower back pressure by fluorous affinity.