Analyzing the surface properties of acrylic-based water-soluble polymers

The surface properties of newly synthesized N-methoxy isopropyl acrylamide, N-methoxy isopropyl methacrylamide, cyclo propyl acrylamide, and cyclo propyl methacrylamide polymers were investigated using inverse gas chromatography. The highest dispersive component of the surface energy value was obtained for cyclo propyl methacrylamide at 30°C. The values obtained for all polymers were decreasing with the increasing temperature. The values obtained for the acidic and the basic parameters revealed strong basic characters for the surface of N-methoxy isopropyl methacrylamide and cyclo propyl methacrylamide polymers and weak basic characters for the surface of N-methoxy isopropyl acrylamide and cyclo propyl acrylamide polymers.     

Orthogonally functionalizable copolymers based on a novel reactive carbonate monomer

A novel N‐hydroxy succinimide‐based carbonate monomer that allows direct synthesis of polymers incorporating a reactive carbonate group in the side chain was synthesized. This new monomer was copolymerized with methyl methacrylate and poly(ethylene glycol) methylether methacrylate using free‐radical polymerization to obtain organo‐ and water‐soluble reactive copolymers. Copolymerization of the activated carbonate monomer with an azide‐containing monomer and N‐hydroxy succinimide‐containing activated ester monomer provided orthogonally functionalizable copolymers. The pendant reactive carbonate groups of the copolymers were functionalized with amines to obtain carbamates. Polymers capable of orthogonal functionalization could be selectively functionalized as desired using subsequent 1,3‐dipolar cycloaddition or amidation reactions. The novel monomer and the copolymers were characterized by ¹H‐NMR, ¹³C‐NMR, and infrared spectroscopy. The efficient stepwise orthogonal functionalization of the copolymers were examined via ¹H‐NMR spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Defining Sets of Full Designs with Block Size Three II

A defining set of a t?(v, k, ??) design is a subcollection of its blocks which is contained in a unique t-design with the given parameters. A minimal defining set is a defining set, none of whose proper subcollections is a defining set. The spectrum of minimal defining sets of a design D is the set {|M| | M is a minimal defining set of D}. The unique simple design with parameters ${{t-\left(v, k, \begin{array}{ll}\left(\begin{array}{ll}v-t\\ k-t\end{array}\right)\end{array}\right)}}$ is said to be the full design on v elements. This paper studies the minimal defining sets of full designs when t = 2 and k = 3. The largest known minimal defining set is given. The existence of a continuous section of the spectrum comprising asymptotically 9v ²/50 values is shown. This gives a quadratic length section of continuous spectrum where only a linear section with respect to v was known before.     

Examination of Polystyrene by Inverse GC: Part 1. Below Glass Transition Temperature

The surface properties of polystyrene were investigated by inverse gas chromatography at infinite dilution region. The standard enthalpy (??H ⁰), entropy (??S ⁰) and free energy (??G ⁰) of adsorption were calculated for the adsorption of n-alkanes (n-hexane, n-heptane, n-octane, n-nonane, n-decane) and some polar probes (acetone, ethyl acetate, DCM, chloroform, THF) on polystyrene. Additionally, the dispersive (London) component of the surface free energy (?? _S ^d ),  surface Lewis acidity (K _A ) and Lewis basicity (K _D ) of polystyrene surface were determined. The values obtained for K _A and K _D by three different methods demonstrate that polystyrene surface has a basic nature.     

Examination of Polystyrene by Inverse GC: Part 2. Above Glass Transition Temperature

In this study, adsorption of some hydrocarbons on polystyrene was investigated with inverse gas chromatography. An experimental study was carried out above glass transition temperature. Thermodynamic parameters belonging to the polymer-solute system, weight fraction activity coefficients, Flory?CHuggins interaction parameter and solubility parameter for solute and polymer were calculated from the obtained data. The results were discussed with respect to the changes in hydrocarbon??s carbon number and temperature.     

Development of Amperometric Glucose Biosensor Based on Reconstitution of Glucose Oxidase on Polymeric 3‐Aminophenyl Boronic Acid Monolayer

An amperometric biosensor for determining glucose based on deflavination of the enzyme glucose oxidase and subsequent reconstitution of the apo‐protein with a complexed flavin adenine dinucleotide (FAD) monolayer is described. The GOx‐reconstituted electrode exhibited excellent electrocatalytic activities towards the reduction and oxidation of hydrogen peroxide as well. The prepared biosensor showed an excellent performance for glucose at +0.5 V with a high sensitivity (5.94 μA/mM) and relatively good response time (～12 s) in a wide concentration range of 1–17 mM (correlation coefficient of 0.9998). The applicability to blood analysis was also evaluated.     

High-rate LDPC codes from partially balanced incomplete block designs

Journal of Algebraic Combinatorics - This paper presents a combinatorial construction of low-density parity-check (LDPC) codes from partially balanced incomplete block designs. Since...     

Orthogonal Trades and the Intersection Problem for Orthogonal Arrays

This work provides an orthogonal trade for all possible volumes \(N \in \mathbb {Z}^+ \setminus \{1,2,3,4,5,7\}\) for block size 4. All orthogonal trades of volume \(N\leqslant 15\) are classified up to isomorphism for this block size. The intersection problem for orthogonal arrays with block size 4 is solved for all but finitely many possible exceptions.