A novel route to poly(2-hydroxyethyl methacrylate) and its amphiphilic block copolymers

The vinyl of the ester group of 2-vinyloxyethyl methacrylate was first selectively reacted with acetic acid to obtain 2-[1-(acetoxy)ethoxy]ethyl methacrylate ( 2 ). This protected monomer was subjected to anionic polymerization in tetrahydrofuran at −60°C in the presence of LiCl, using 1,1-diphenylhexyllithium as initiator. The molecular weight of the polymer could thus be controlled and a narrow molecular weight distribution obtained. The protecting group, 1-(acetoxy)ethyl, could be easily eliminated (by quenching the polymerization reaction with methanol and water) to generate poly(2-hydroxyethyl methacrylate) (poly(HEMA)). Block copolymers were also prepared by the sequential anionic polymerization of MMA and 2 or styrene and 2 . They possess narrow molecular weight distributions, and controlled molecular weights and compositions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1865–1872, 1998     

Fourier transform infrared study of poly (2-hydroxyethyl methacrylate) PHEMA

 Fourier transform infrared spectra in the wave number range 450–4500 cm^-1 of poly (2-hydroxy-ethyl methacrylate) PHEMA have been studied as functions of water content in the range 38–2.6 wt% and of temperature in the range 300–373 K. The results show changes in the intensities of the stretching frequencies of the carbonyl band, H–O–H bending vibration and O–H stretching vibration with a change in water content and temperature. The results confirm two types of water in the hydrogel polymer system, tightly bound water and loosely bound water. At low concentrations, water is mainly hydrogen-bonded to the polymer and is described as tightly bound water. However, at water concentrations greater than 18% by weight, part of the water exists in a different form and behaves as loosely bound water. For concentrations over 30%, there is some evidence that excess water behaves more loosely bound somewhat like bulk water. Infrared spectroscopic results supplement those obtained by means of NMR by Smyth et al. and by dielectric spectroscopy. Our results also show that some of the water continues to be hydrogen bonded to the polymer until at least a temperature of 373 K when the bulk water should have evaporated. FTIR is found to yield greater site-specific insight into the local behaviour of water in hydrated PHEMA. Received: 22 August 1996 Accepted: 11 November 1996     

Electrospinning of the hydrophilic poly (2-hydroxyethyl methacrylate) and its copolymers with 2-ethoxyethyl methacrylate

The goal was to electrospin 2-hydroxyethyl methacrylate — based biocompatible polymers and prepare submicron fibres (nanofibers) for biomedicinal applications. Syntheses of poly(2-hydroxyethyl methacrylate) (HEMA) and its copolymer with 2-ethoxyethyl methacrylate (EOEMA), and their characterization by viscometry and molecular weight are described. Their relation to electrospinning is discussed. Electrospinning of HEMA homopolymer from water-ethanol is successful for molecular weights 6.31 × 10⁵ and 1.80 × 10⁶ g/mol. Electrospinning of HEMA/EOEMA copolymers is feasible from ethanol.      

Swelling behaviour of crosslinked hydrogels based on (2-hydroxyethyl methacrylate) with a zwitterionic comonomer (1-3-sulfopropyl-2-vinyl-pyridinium-betaine)

Copolymeric hydrogels were prepared by the chemically initiated free radical copolymerization in aqueous solution of mixtures of [1-(3-sulfopropyl)-2-vinyl-pyridinium-betaine] (SPV) and (2-hydroxyethyl methacrylate) (HEMA) in the presence of a crosslinking agent N,N′-methylene-bis-acrylamide (MBA). The hydrogels were swollen to equilibrium in water and aqueous KSCN at 298 K and their swelling behaviour has been investigated using gravimetric measurements. The effects of the concentration of KSCN and the mole fraction of SPV in the feed (F_s) have been noted and discussed. The main findings are:(a) In water, the water content (W₁) of copolymeric hydrogels is insensitive to SPV content at F_s ? 0.45. In contrast, W₁ decreases sharply with decreasing F_s within the range of 0 < F_s < 0.45. (b) In aq. KSCN, the degree of total swelling (W) exceeds the value in pure water, the enhancement in swelling being most marked at low values of [KSCN]. The content of water within the hydrogel increases with KSCN concentration in the swelling medium for low values of [KSCN], but thereafter falls with further increase in salt concentration. In contrast, the salt content within the swollen hydrogel displays a continuous increase with increasing [KSCN]. All these results of item (b) are for copolymeric hydrogels within the full range of F_s (0 < F_s < 1). (c) at a fixed aq. KSCN concentration, both W and W₁ increase sharply with increasing F_s over the entire range of copolymer composition.     

Covalent immobilization of invertase on chemically activated poly(2-hydroxyethyl methacrylate) microbeads

Properties of invertase immobilized on poly(2-hydroxyethyl methacrylate) microbeads activated by epichlorohydrin or cyanuric chloride were studied. After 20 repeated uses for 3 days, the activity of the immobilized enzyme was 92–93%. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1793–1797, October, 2006.     

含氨基聚甲基丙烯酸羟乙酯树脂对胆红素的吸附性能研究

以交联聚甲基丙烯酸羟乙酯树脂为载体,以己二胺和多乙烯多胺为功能基制备了一系列胆红素吸附剂,研究了它们在不同吸附温度、离子强度和胆红素浓度等条件下,对胆红素的吸附性能的影响.研究表明,该类吸附剂对胆红素具有良好的吸附性能,其中以己二胺和质子化己二胺为功能基的吸附剂对胆红素的吸附作用最佳.     

On the preparation of stable poly(2-hydroxyethyl methacrylate) nanoparticles

A comprehensive experimental study of aqueous heterophase homopolymerization of 2-hydroxyetyl methacrylate revealed special conditions that must be fulfilled in order to obtain stable latex particles in the nanometer size range. The results clearly show that the formation and the stability of this kind of hydrophilic latex particle strongly depends on the hydrophobic-hydrophilic properties of both the initiating radicals and the stabilizers. Hydrophobic initiators in combination with sodium alkyl sulfate surfactants of proper chain lengths or ionic surface-active initiators lead to stable latex particles. In the latter case the particles keep their identity and spherical shape even after drying of the aqueous dispersion.     

Preparation of micron-size monodisperse poly(2-hydroxyethyl methacrylate) particles by dispersion polymerization

Dispersion polymerization of 2-hydroxyethyl methacrylate using four categories of polymeric stabilizers in a mixture of good and poor solvents was performed to produce polymeric particles. The stabilizers employed were methyl methacrylate and styrene homopolymers, methacryloyl-terminated poly(methyl methacrylate) and polystyrene macromonomers, an amphiphilic poly(methyl methacrylate-co-methacrylic acid-graft-styrene), and polybutadiene derivatives containing reactive vinyl groups. Dispersion copolymerization with a small amount of the macromonomer gave micron-size particles with relatively narrow size distribution. The amphiphilic graft copolymer and the polybutadiene derivatives also afforded monodisperse particles. The mixed ratio between good and poor solvents greatly affected the particle size and size distribution. © 1996 John Wiley & Sons, Inc.     

Streptavidin-modified magnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microspheres for selective isolation of bacterial DNA

The dispersion copolymerization of 2-hydroxyethyl methacrylate (HEMA) with glycidyl methacrylate (GMA) in a toluene/2-methylpropan-1-ol mixture in the presence of Fe₃O₄ nanoparticles coated with oleic acid, produced monodisperse magnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-GMA)) microspheres. Oxirane groups of the microspheres were ammonolyzed and then functionalized with streptavidin using cyanuric chloride. The final product contained 0.67 mg of streptavidin per gram of wet magnetic P(HEMA-GMA) microspheres. The microspheres were characterized by elemental analysis, scanning electron microscopy, IR, UV–VIS and atomic absorption spectroscopy. The streptavidin-modified magnetic P(HEMA-GMA) microspheres were used for immobilization of biotinylated DNA and subsequent selective isolation of target DNA from complex samples using DNA/DNA hybridisation. Based on the highly selective recognition of streptavidin with a biotin-labeled DNA probe, DNA sensor was constructed for magnetic separation of DNA from real samples.     

Interpolymer complexes of poly(acrylic acid) with poly(2-hydroxyethyl acrylate) in aqueous solutions

Complexes formed from poly(acrylic acid) and poly(2-hydroxyethyl acrylate) were studied in aqueous solutions by viscometric, turbidimetric, FTIR spectroscopic, and thermogravimetric analysis methods. The formation of interpolymer complexes stabilized by hydrogen bonds was observed. It was found that the compositions of these interpolymer complexes are strongly dependent on the concentration of polymers, the order of mixing the solutions, and the pH. It was demonstrated that the complexation ability of poly(2-hydroxyethyl acrylate) is relatively low compared to other known nonionic water-soluble polymers. However, it can be significantly increased via hydrophobic modification of the poly(acrylic acid) using cetyl pyridinium bromide.     

A mixed film composed of oligonucleotides and poly(2-hydroxyethyl methacrylate) brushes to enhance selectivity for detection of single nucleotide polymorphisms

Preliminary studies of mixed films composed of oligonucleotides and poly(2-hydroxyethyl methacrylate) (PHEMA) have recently been shown to enhance the selectivity for detection of 3 base-pair mismatched (3 bpm) oligonucleotide targets. Evaluation of selectivity for detection of single nucleotide polymorphisms (SNP) using such mixed films has now been completed. The selectivity was quantitatively determined by considering the sharpness of melt curves and melting temperature differences (ΔT_m) for fully complementary targets and SNPs. Stringency conditions were investigated, and it was determined that the selectivity was maximized when a moderate ionic strength was used (0.1-0.6 M). Increases of ΔT_m when using mixed films were up to 3-fold larger compared to surfaces containing only immobilized oligonucleotide probes. Concurrently, increases in sharpness of melt curves for 1 bpm targets were observed to be up to 2-fold greater for mixed films. The co-immobilization of PHEMA resulted in a more homogeneous distribution of oligonucleotide probes on surfaces. Lifetime measurements of fluorescence emission from immobilized oligonucleotide probes labeled with Cy3 dye indicated the difference in microenvironment of immobilized oligonucleotides in the presence of PHEMA.     

Graft polymerization of 2-hydroxyethyl methacrylate via ATRP with poly(acrylonitrile-co-p-chloromethyl styrene) as a macroinitiator

Amphiphilic graft copolymers are excellent additives for the development of antifouling membranes by nonsolvent induced phase separation. We report a convenient approach to the synthesis of novel graft copolymers with hydrophobic polyacrylonitrile (PAN) backbones and hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) side chains. Atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate was carried out with poly(acrylonitrile-co-p-chloromethyl styrene) (PAN-co-PCMS) as a macroinitiator in the presence of CuCl/2,2’-bipyridine at 50 °C in dimethyl sulfoxide. Kinetics of the graft polymerization was also evaluated. The synthesis of poly(acrylonitrile-co-p-chloromethyl styrene-g-2-hydroxyethyl methacrylate) (PAN-co-(PCMS-g-PHEMA)) can be relatively controlled when CMS (the ATRP sites) unit in the macroinitiator is around 5 mol%. Both the macroinitiators and graft copolymers were characterized by FTIR, NMR and GPC. The surface morphology and wettability of the copolymer films were studied by AFM and water contact angle measurement, respectively. We demonstrate that phase segregation between the PAN-co-PCMS backbones and the PHEMA side chains takes place and the surface hydrophilicity of the graft copolymers increases with the length of the PHEMA side chains. Because these amphiphilic graft copolymers can be synthesized in mass, they will be useful as latent additives for the fabrication of advanced PAN separation membranes.     

Synthesis and characterization of poly(butylene terephthalates) modified by hydroquinone bis(2-hydroxyethyl)ether

A series of thermoplastic poly(butylene-co-hydroquinone bis(2-hydroxyethyl)ether terephthalates) (PBHT), with different molar ratios of hydroquinone bis(2-hydroxyethyl)ether (HQEE)/1,4-butanediol 9/91, 18/82 and 27/73, were synthesized via melt polycondensation. The compositions, thermodynamics and crystallization properties of the obtained copolyesters were characterized in detail by ¹H NMR, differential scanning calorimeters (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). These results showed that the PBHTs were successfully synthesized, and the incorporation of the HQEE group significantly improved thermal properties of the polymers. However, HQEE did not change the crystal structure of PBT. The T_m values of the copolymers decreased (from 208?°C to 174?°C) with increasing content of HQEE segments, on the contrary, T_g values increased (from 37?°C to 43?°C). The temperatures for 5% weight loss did not decrease and appeared at a range of 373–377?°C.     

一种无计有机聚合物中间体——六(甲基丙烯酸羟乙酯)三聚膦腈的合成

六氯三聚膦腈;一种无计有机聚合物中间体——六(甲基丙烯酸羟乙酯)三聚膦腈的合成     

Glass transition of thin films of poly(2-vinyl pyridine) and poly(methyl methacrylate): nanocalorimetry measurements

Glass transitions were observed in thin films of poly(2-vinyl pyridine) (P2VP) and poly(methyl methacrylate) (PMMA) using a scanning nanocalorimetry technique which has both high sensitivity (10⁻⁹ J/K) and high scan rates (10⁴-10⁵ K/s). Samples were deposited by the spin-cast method. The thickness of samples was 100-400 nm. Glass transition temperature, obtained by nanocalorimetry, is shifted toward higher temperatures by 10-20 K and activation enthalpy of glass transition is shifted to lower values by factor of 2-4. The glass transition characteristics of both polymers are discussed in terms of the standard Tool-Narayanaswamy-Moynihan (TNM) multi-parameter model.     

The role of water in structural changes of poly(N-isopropylacrylamide) and poly(N-isopropylmethacrylamide) studied by FTIR, Raman spectroscopy and quantum chemical calculations

Temperature-induced phase transition in water solutions of poly(N-isopropylacrylamide) (PNIPAM) and poly(N-isopropylmethacrylamide) (PNIPMAM) have been studied by ATR FTIR and Raman spectroscopy in combination with quantum chemical calculations. The presence or absence of the α-methyl group has a strong effect on the physical structure of water solutions. Although the hydrophobic interactions for PNIPMAM and PNIPAM are very similar, PNIPMAM with additional methyl group exhibits significantly weaker intermolecular interactions between the amide groups. That effect is the cause of the higher transition temperature T_t by about 8 °C for PNIPMAM compared to PNIPAM due to the formation of larger compact structures. The presence of the methyl group is significant for the reversibility of the temperature transition during the backward cooling as the dissolution of more stable compact PNIPMAM requires overcoming of a higher energy barrier and shows a strong hysteresis.     

Bacterial adhesion-resistant poly(2-hydroxyethyl methacrylate) derivative for mammalian cell cultures

In an attempting to find new biomaterials for mammalian cell culture, PHEMA derivatives with ester side groups are synthesized by one-step polymer-analogous reaction. These polymers show excellent antifouling properties against S. epidermidis and P. aeruginosa while their cytotoxicity and proliferation activity for HDF cell are on a similar level as commercially available TCPS. The interesting bioadhesion property is systematically correlated with surface properties of the PHEMA derivatives.     

Terpolymerization of methyl methacrylate, poly(ethylene glycol) methyl ether methacrylate or poly(ethylene glycol) ethyl ether methacrylate with methacrylic acid and sodium styrene sulfonate: determination of the reactivity ratios

Materials bearing ionic monomers were obtained through free radical terpolymerization of methyl methacrylate (MMA), poly(ethylene glycol) methyl ether methacrylate (PMEM) or poly(ethylene glycol) ethyl ether methacrylate (PEEM) with methacrylic acid (MA) and sodium styrene sulfonate (NaSS). The reactions were carried out in dimethyl sulfoxide using azobis(isobutyronitrile) as initiator. The reactivity ratios of the different couple of monomers were calculated according to the general copolymerization equation using the Finnemann-Ross, Kelen-Tüdos and Tidwell-Mortimer methods. The values of the reactivity ratios indicate that the different monomer units can be considered as randomly distributed along the chains for terpolymerizations of MMA, PMEM or PEEM with MA and NaSS. The average composition of the comonomers in the different terpolymers were calculated, showing a good agreement between the experimental and theoretical compositions. The instantaneous compositions are constant until about 70% of conversion. For higher conversions, the insertion of ionic monomers increases or decreases according to the system studied.     

The sorption mechanism of Au(III) on sulfur-containing chelating resin poly[4-vinylbenzyl (2-hydroxyethyl) sulfide]

The sorption mechanism of sulfur-containing chelating resin, poly[4-vinylbenzyl (2-hydroxyethyl) sulfide], towards Au(III) was investigated by Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD). It was showed that the sulfide bond in the resin was oxidized into sulfoxide and sulfone bond, and Au(III) was deoxidized into Au(0).     

Analysis of amino acids and proteins using a poly(methyl methacrylate) microfluidic system

Plastic microchips are very promising analytical devices for the high-speed analysis of biological compounds. However, due to its hydrophobicity, their surface strongly interacts with nonpolar analytes or species containing hydrophobic domains, resulting in a significant uncontrolled adsorption on the channel walls. This paper describes the migration of fluorescence-labeled amino acids and proteins using the poly(methyl methacrylate) microchip. A cationic starch derivative significantly decreases the adsorption of analytes on the channel walls. The migration time of the analytes was related to their molecular weight and net charge or pI of the analytes. FITC-BSA migrated within 2 min, and the theoretical plate number of the peak reached 480,000 plates/m. Furthermore, proteins with a wide range of pI values and molecular weights migrated within 1 min using the microchip.