Hydrogels of poly(hydroxyethyl methacrylate) and hydroxyethyl methacrylate—glycerol monomethacry-late copolymers

Hydrophilic three-dimensional polymer networks (hydrogels) were prepared from hydroxyethyl methacrylate (HEMA) and the copolymer HEMA and glycerol monomethacrylate (GMMA). The equilibrium water content of the hydrogels in water was investigated as a function of the initial dilution of the polymerization mixture, the type of solvent, and the hydrophilicity of the polymer. The initial dilution was found to have a decisive effect on the swelling or deswelling of hydrogels after the completion of the gel formation. With relatively less hydrophilic hydrogels, there is a critical initial dilution to produce the gel which does not swell or deswell in water after the gel formation. This “isovolumic” initial dilution shifts toward a higher dilution as the hydrophilicity of the hydrogels increases; however, when hydrophilicity of the polymer rises above a certain point, gels always swell in water. Permeability of oxygen through hydrogels was also studied.     

Creatinine imprinted poly(hydroxyethyl methacrylate) based cryogel cartridges

Creatinine imprinted cryogel (MIP) cartridge was prepared with functional monomer N-methacryloyl-(L)-histidinemethylester (MAH) under frozen conditions. Creatinine adsorption studies and selectivity of MIP cryogel were evaluated in aqueous solution and artificial urine sample. Maximum adsorbed amount of creatinine was calculated as 6.83 mg/g polymer for MIP cryogel. Langmuir and Freundlich adsorption isotherm models were used to investigate the adsorption behaviour of creatinine. In the artificial urine sample; recovery amounts of creatinine were found 34.7–46.2%. Creatinine imprinted cryogel (MIP) cartridge recognized creatinine, 4.58 and 4.37 times greater competitive molecules. MIP cryogel catridge was repeatedly used many times for adsorption desorption cycles.     

Characterisation of hydroxyapatite surface modified by poly(ethylene glycol) and poly(hydroxyethyl methacrylate) grafting

Hydroxyapatite (HA) has many applications in medicine as a biocompatible and bioactive biomaterial. Numerous studies have shown that modification of the HA surface can improve its biological and chemical properties. However, little is known about the surface properties of modified materials. In this paper the influence of organic polymers: polyethylene glycol (PEG) and polyhydroxyethyl methacrylate (pHEMA) on the surface properties and surface chemistry of hydroxyapatite (HA) is presented. The surface properties of modified HA were characterised by the FT-IR, XPS, BET, and zeta potential measurements. Specific surface area was determined by BET. Infrared and XPS spectra confirmed the presence of PEG and pHEMA on the surface of HA. The BET N₂ adsorption revealed slight changes in the HA surface chemistry after grafting modification. The surface chemical properties of the HA were considered to be based on the zeta potential. The decrease in zeta potential results in the increasing stability of the modified material and also in the reduction of bacterial adhesion. The reaction for surface modification of HA is proposed and described.     

High capacity binding of antibodies by poly(hydroxyethyl methacrylate) nanoparticles

Poly(hydroxyethyl methacrylate) (PHEMA) nanoparticles with an average size of 150 nm in diameter and with a poly-dispersity index of 1.171 were produced by a surfactant free emulsion polymerization. Specific surface area of the PHEMA nanoparticles was found to be 1779 m(2)/g. Reactive imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was used as a pseudo-specific ligand. IMEO was attached covalently onto the nanoparticles. PHEMA-IMEO nanoparticles were used for the affinity binding of immunoglobulin-G (IgG) from human plasma. To evaluate the degree of IMEO loading, the PHEMA nanoparticles were subjected to Si analysis by using flame atomizer atomic absorption spectrometer and it was estimated as 64.5 mg/g of polymer. The nanoparticles were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). IgG binding onto the PHEMA nanoparticles was found to be 5.2 mg/g. Much higher binding values (up to 843 mg/g) were obtained for the PHEMA-IMEO nanoparticles. IgG could be repeatedly bound and eluted on PHEMA-IMEO nanoparticles without noticeable loss in the IgG binding capacity.     

Cysteine functionalized poly(hydroxyethyl methacrylate) monolith for heavy metal removal

The aim of this study was to investigate the performance of monoliths composed of hydroxyethyl methacrylate (HEMA) to which N-methacryloyl-(L)-cysteine methyl ester (MAC) was polymerized for removal of heavy metal ions. Poly(HEMA-MAC) monolith was produced by bulk polymerization. Poly(HEMA-MAC) monolith was characterized by FTIR and scanning electron microscopy (SEM). The poly(HEMA-MAC) monolith with a swelling ratio of 89%, and containing 69.4 μmol MAC/g were used in the adsorption studies. Adsorption capacity of the monolith for the metal ions, i.e., Cu²⁺, Cd²⁺, Zn²⁺, Hg²⁺, and Pb²⁺ were investigated in aqueous media containing different amounts of the ions (10–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(HEMA-MAC) monolith were 68.2 mg/g for Zn²⁺, 129.2 mg/g for Cu²⁺, 245.8 mg/g for Pb²⁺, 270.2 mg/g for Hg²⁺, and 284.0 mg/g for Cd²⁺. pH significantly affected the adsorption capacity of MAC incorporated monolith. The competitive adsorption capacities were 587 μmol/g for Zn²⁺, 1646 μmol/g for Cu²⁺, 687 μmol/g for Pb²⁺, 929 μmol/g for Hg²⁺, and 1993 μmol/g for Cd²⁺. The chelating monolith exhibited the following metal ion affinity sequence on molar basis: Cd²⁺ > Cu²⁺ > Hg²⁺ > Pb²⁺ > Zn²⁺. The formation constants of MAC–metal ion complexes have been investigated applying the method of Ruzic. The calculated values of stability constants were 5.28 × 10⁴ L/mol for Cd²⁺, 4.16 × 10⁴ L/mol for Cu²⁺, 2.27 × 10⁴ L/mol for Hg²⁺, 1.98 × 10⁴ L/mol for Pb²⁺, and 1.25 × 10⁴ L/mol for Zn²⁺. Stability constants were increased with increasing binding affinity. The chelating monoliths can be easily regenerated by 0.1 M HNO₃ with higher effectiveness. These features make poly(HEMA-MAC) monolith a potential adsorbent for heavy metal removal.     

Modification of capillary electrophoresis capillaries by poly(hydroxyethyl methacrylate), poly(diethylene glycol monomethacrylate) and poly(triethylene glycol monomethacrylate)

Modification of capillary electrophoresis (CE) capillaries by poly(hydroxyethyl methacrylate) (poly(HEMA), poly(diethylene glycol monomethacrylate) (poly(DEGMA) and poly(triethylene glycol monomethacrylate) (poly(TEGMA), was studied. Methods based on physical adsorption of the modifier and on its chemical binding were compared on the basis of the electroosmotic flow (EOF) reproducibility, the EOF dependence on the pH, the symmetry of the peak of positively charged tyramine, the stability of the coating and the separation of standard and milk proteins in the modified capillaries. Reproducible coatings were obtained by chemical binding of the polymers to the capillary walls and by coating with a solution of a polymer, as also demonstrated by the atomic force microscopy.     

Dye attached poly(hydroxyethyl methacrylate) cryogel for albumin depletion from human serum

Cibacron Blue F3GA was immobilized on poly(hydroxyethyl methacrylate) cryogel and it was used for selective and efficient depletion of albumin from human serum. The poly(hydroxyethyl methacrylate) was selected as the basic component because of its inertness, mechanical strength, chemical and biological stability, and biocompatibility. Cibacron Blue F3GA was covalently attached to the poly(hydroxyethyl methacrylate) cryogel to produce poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel affinity column. The poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel was characterized with respect to gelation yield, swelling degree, total volume of macropores, Fourier Transform Infrared spectroscopy, and scanning electron microscopy. It was found that the maximum amount of adsorption (343 mg/g of dry cryogel) obtained from experimental results is very close to the calculated Langmuir adsorption capacity (345 mg/g of dry cryogel). The maximum adsorption capacity for poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel column was obtained as 950 mg/g of dry cryogel for nondiluted serum. The adsorption capacity decreased with increasing dilution ratios while the depletion ratio of albumin remained as 77% in serum sample. Finally, the poly(hydroxyethyl methacrylate)-Cibacron Blue F3GA cryogel was optimized for using in the fast protein liquid chromatography system for rapid removal of the high abundant proteins from the human serum.     

Preparation and characterization of carboxylic-containing poly(methyl methacrylate) nanolatexes

Poly(methyl methacrylate) (PMMA)-based latex particles bearing carboxylic groups at the surface were prepared via emulsion polymerization. The polymerization recipe and process were optimized in order to target monodisperse particles with diameters around 100 nm. The polymerizations were performed using 4,4-azobis(4-cyanopentanoic) acid (ACPA) as initiator and sodium dodecyl sulphate (SDS) as surfactant. The polymerization conversion was determined by both gas chromatography and gravimetry. The final latexes were characterized with respect to particle size, size distribution, surface charge density, electrokinetic properties (i.e. electrophoretic mobility vs pH and ionic strength) and colloidal stability (i.e. coagulation rate constants vs pH and stability factor vs ionic strength).     

Preparation and characterization of poly (N-isopropylacrylamide-co-dimethylaminoethyl methacrylate) microgel latexes

Monodisperse cationic thermosensitive latex microgels have been prepared by radical-initiated precipitation polymerization of N-isopropylacrylamide, methylene bisacrylamide using 2,2′-azobis(2-amidinopropane hydrochloride) as an initiator and dimethylaminoethyl methacrylate (DMAEMA) as a cationic monomer. The final microgel latexes were characterized with respect to water-soluble polymer formation, particle size and size distribution. Adding cationic monomer (DMAEMA) was found to drastically affect the particle size, but not the size distribution as observed both by transmission electron microscopy and quasielastic light scattering (QELS). However, too high a DMAEMA concentration in the feed composition led to enhanced formation of water-soluble polymer. The volume phase-transition temperature of cleaned microgels examined by QELS (particle size versus temperature) was found to be around 32 °C and was slightly dependent on the concentration of the cationic monomer. The volume phase-transition temperature range becomes broader with increasing cationic monomer concentration. In addition, the pH of the polymerization medium was found to affect the final particle size and amount of water-soluble polymer formed. Received: 29 March 2001 Accepted: 2 July 2001     

Synthesis,structure, and properties of silver nanocomposite materials with poly(hydroxyethyl methacrylate) matrix

The mechanism of photoreduction of silver particles from colloidal solutions in 2-hydroxyethyl methacrylate, followed by its photopolymerization for preparing antirefl ection coatings, is considered.     

Voltage-tunable volume transitions in nanoscale films of poly(hydroxyethyl methacrylate) surfaces grafted onto gold

Surface grafting of a polymerizable monomer onto Au was used to produce nanometer-scale planar hydrogel films with controllable volume. A self-assembled monolayer of 11-mercaptoundecanoic acid on a planar Au surface was activated through water-soluble carbodiimide and N-hyroxysuccinimide followed by reaction with 2-aminomethacrylate to produce a methacrylate-terminated surface layer, which readily polymerized under UV radiation in the presence of hydroxyethyl methacrylate monomer, ethylene glycol dimethacrylate cross-linker, and a photoinitiator. The reaction steps were characterized by external reflection mode Fourier transform IR spectroscopy. Under controlled UV exposure, thin (3 nm < d < 10 nm) hydrogel films were obtained from 1:1 ethanol/H(2)O. Surface plasmon resonance measurements were used to characterize both the synthesis of the hydrogel and the potential-induced volume changes. The nanometer-scale hydrogels thus produced undergo reproducible changes in thickness, when a potential is applied across the film. Thickness changes increasing with applied potential were obtained for both voltages in the range |V(appl)| 相似文献   

Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres

~~Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres~~     

Synthesis and miscibility studies of [60]fullerenated poly(2‐hydroxyethyl methacrylate)

[60]Fullerenated poly(2‐hydroxyethyl methacrylate)s containing 0.6–3.0 wt % C₆₀ were synthesized. These polymers are soluble in methanol and N,N‐dimethylformamide (DMF). [60]Fullerenated poly(2‐hydroxyethyl methacrylate)s with higher C₆₀ contents are only sparingly soluble in DMF and virtually insoluble in other organic solvents. A loading of 1.2 wt % C₆₀ in poly(2‐hydroxyethyl methacrylate) does not greatly affect its miscibility with poly(N‐vinyl‐2‐pyrrolidone), poly(1‐vinylimidazole), and poly(4‐vinylpyridine). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1157–1166, 2002     

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with poly(butadiene-block-methyl methacrylate)

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with butadiene-methyl methacrylate diblock copolymers has been investigated by transmission electron microscopy. When the diblock copolymers are added to the blends, the size of PB particles decreases and their size distribution gets narrower. In PB/PMMA7.6K blends with P(B-b-MMA)25.2K as a compatibilizer, most of micelles exist in the PMMA phase. However, using P(B-b-MMA)38K as a compatibilizer, the micellar aggregation exists in PB particles besides that existing in the PMMA phase. The core of a micelle in the PMMA phase is about 10 nm. In this article the influences of temperature and homo-PMMA molecular weight on compatibilization were also examined. At a high temperature PB particles in blends tend to agglomerate into bigger particles. When the molecular weight of PMMA is close to that of the corresponding block of the copolymer, the best compatibilization result would be achieved. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 85–93, 1998     

Water-compatible poly (hydroxyethyl methacrylate) polymer sorbent for miniaturized syringe assisted extraction of sulfonamides in milk

A simple, convenient, and economic self-assembly miniaturized syringe assisted extraction (mini-SAE) using poly (hydroxyethyl methacrylate) polymer (PHEMA) as sorbent coupled with liquid chromatography was proposed for rapid screening of sulfadiazine (SD) and sulfamonomethoxine (SMM) in milk. The water-compatible PHEMA was synthesized by reversible addition-fragmentation chain transfer precipitation polymerization using trithiocarbonate as chain transfer agent and methanol–water system as reaction medium. The obtained PHEMA sorbent showed good affinity to sulfonamides and was successfully applied as a special sorbent for a mini-SAE device for simultaneous extraction and isolation of SD and SMM in milk samples. Under the optimum condition, good linearity was obtained in a range of 7.0–700 ng g⁻¹ (r ≥ 0.9995) and the average recoveries of SD and SMM at three spiked levels were ranged from 85.6 to 100.3% with the relative standard deviations (RSD) ≤6.5%. The presented PHEMA-mini-SAE protocol could be potentially applied as an alternative tool for analyzing the residues of SAs in complicated biological samples.     

Surface modification of poly(2‐hydroxyethyl methacrylate) hydrogel for contact lens application

The present study examined poly(2‐hydroxyethyl methacrylate) (PHEMA)‐based hydrogels that have been extensively used in biomedical applications, including contact lens. In this research, we aimed to reduce adsorption of protein components from tears and bacterial deposition by surface modification of the hydrogel with different functional groups that included carboxylic acid, primary amine, and quaternary ammonium. The PHEMA was treated with a solution of sulfuric acid for partial hydrolysis of the HEMA ester groups to induce acid groups on the surface of the hydrogel. Carboxylic acid groups of the modified PHEMA were converted to primary amine and quaternary ammonium groups via carbodiimide chemistry. The surface physical and chemical properties of different samples were investigated by atomic force microscopy and X‐ray photoelectron spectroscopy, respectively. We conducted the bicinchoninic acid assay to evaluate protein deposition from artificial tear fluid on samples. Antibacterial properties of the modified hydrogels were investigated with a culture of Staphylococcus aureus, one of the major causes of eye infections. Our data showed that positively charged amine and ammonium groups efficiently resisted protein adsorption and bacterial deposition compared to alcohol and carboxylic acid groups.     

Preparation and properties of cross-linked fluorescent poly(methyl methacrylate) latex colloids

We report a single step preparation of monodisperse fluorescent poly(methyl)methacrylate (PMMA) lattices cross-linked with ethylene glycol dimethacrylate with radii in the range 150-1000 nm using dispersion polymerization. The particles are applied as fluorescent cores in core-shell PMMA particles for confocal microscopy (Dullens et al. Langmuir 2003, 19, 5963). Contrary to un-cross-linked particles, these cross-linked colloids are stable in good solvents for PMMA as well. Therefore we studied the properties of the cross-linked PMMA particles in the good solvents tetrahydrofuran (THF), chloroform, and toluene using light scattering and confocal scanning laser microscopy. We show that the particles swell instantaneously and that their volume can increase up to more than seven times their volume in poor solvents. Further, it is very likely that the particles are charged in THF.     

Preparation of a uniform poly(methyl methacrylate) macromonomer and its polymerization

Syndiotactic poly(methyl methacrylate) (st-PMMA) macromonomer having methacryloyl end group was prepared from st-PMMA living anion and separated into uniform macromonomers by means of supercritical fluid chromatography. A uniform macromonomer with the degree of polymerization of 32 was polymerized radically in benzene at 60°C. The uniform dimer, trimer and tetramer of the uniform macromonomer were isolated from the polymerization product by means of gel-permeation chromatography (GPC). The intrinsic viscosity ([η]) in tetrahydrofuran of these uniform comblike polymers was determined by GPC/differential viscometric analysis. The plot of logarithmic [η] against logarithmic molecular weight indicated that the trimer and tetramer assume a little shrinking molecular shape as compared with the unimer and dimer.