Partitioning of Functional Monomers in Emulsion Polymerization: Distribution of Carboxylic Acid and Hydroxy (Meth)acrylate Monomers between Water and Polymers

We have studied the distribution of vinyl acid and hydroxy (meth)­acrylate monomers between water and a variety of styrene, acrylate, and methacrylate homopolymers and copolymers. From equilibrium distribution data, we determined the Flory–Huggins monomer–polymer interaction parameters (χ) using appropriate water phase activity coefficients (γ). For the functional monomers studied here, their χ values with (meth)­acrylic polymers are all below 0.5 and are often negative. Those with polystyrene are greater than 0.5. This comparison highlights the influence of hydrogen bonding on the water–polymer phase distribution in latex systems. Within functional monomer concentration ranges typical in emulsion polymerization, we find both the χ values and distribution coefficient to be linearly correlated with the molar volume of the polymer. With proper χ and γ values, the complete distribution across all phases for functional monomers can be determined, both for single-component systems as well as for multimonomer and copolymer environments

Monte Carlo Simulations of Free Radical Polymerizations with Divinyl Cross-Linker: Pre- and Postgel Simulations of Reaction Kinetics and Molecular Structure

A computationally efficient Monte Carlo method was used to simulate the reaction kinetics and molecular structure development during free-radical copolymerizations with divinyl monomers. A single parameter was used to describe the reduced reactivity of the pendent vinyl groups incorporated within the polymer backbone. The simulation results were compared with published experimental data for the bulk copolymerization of methyl methacrylate with different levels of ethylene glycol dimethacrylate. The model was able to effectively predict the reaction kinetics, the gel point, and sol–gel fractions in both the pre- and postgel regimes, including the swelling index of the gel. In the postgel regime the cross-linked molecule becomes the primary locus of reactions, and all chains eventually become part of this massive cross-linked polymer network. The Monte Carlo method allows the determination of the complete molecular structure as it evolves with time, including properties like cross-linking density, number of free chain ends, primary cycles and loops, and the fraction of unreacted pendent vinyl groups

Data_Sheet_1.docx

<p>Selective and rapid detection of biomarkers is of utmost importance in modern day health care for early stage diagnosis to prevent fatal diseases and infections. Among several protein biomarkers, the role of lysozyme has been found to be especially important in human immune system to prevent several bacterial infections and other chronic disease such as bronchopulmonary dysplasia. Thus, real-time monitoring of lysozyme concentration in a human body can pave a facile route for early warning for potential bacterial infections. Here, we present for the first time a label-free lysozyme protein sensor that is rapid and selective based on a graphene field-effect transistor (GFET) functionalized with selectively designed single-stranded probe DNA (pDNA) with high binding affinity toward lysozyme molecules. When the target lysozyme molecules bind to the surface-immobilized pDNAs, the resulting shift of the charge neutrality points of the GFET device, also known as the Dirac voltage, varied systematically with the concentration of target lysozyme molecules. The experimental results show that the GFET-based biosensor is capable of detecting lysozyme molecules in the concentration range from 10 nM to 1 µM.</p

Supplemental material for Dynamic Aggregation of Poly-N-Isopropylacrylamide Characterized Using Second-Order Scattering

<p>Supplemental material for Dynamic Aggregation of Poly-N-Isopropylacrylamide Characterized Using Second-Order Scattering by Luke A. Fulton, Pei Zhang, W. Rudolf Seitz, John G. Tsavalas and Roy P. Planalp in Applied Spectroscopy</p