Ethyltrimethylammonium Chloride Research Articles

Formation of continuous dense polymer layer at the surface of hollow fiber using a photografting process

ABSTRACTThe surface modification of a PES hollow fiber by UV photografting has been investigated in order to graft a dense polymer layer. The study focused on a UV photografting process, starting from a monomer solution, enabling the thickness and regularity of the grafted polymer to be followed. 2‐(Acryloyloxy)ethyl trimethylammonium chloride was polymerized on the surface of the PES membrane. Modified membranes were characterized by SEM, FTIR spectroscopy, and liquid and gas permeability. A dense layer of poly(2‐(acryloyloxy)ethyl trimethylammonium chloride) was obtained when a photoinitiator and a photocrosslinker were used. Polymerization of the ammonium material also occurred inside the pores of the membrane. With pretreatment and an increase of the irradiation time, the thickness of the grafted polymer decreased and gas permeability reached measurable levels. However, a CO2/N2 selectivity of around 1 was found which suggested the presence of defects in the grafted layer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41514.

Polyelectrolyte complexation between cationic and anionic polyelectrolytes with complementary polymer-bound reactive groups of amine and acetoacetate: effect of mono- and divalent salts

The copolymers of methacrylic acid with 0–50 % of 2-(methacryloyloxy)ethyl acetoacetate, and the copolymers of 2-(methacryloyloxy)ethyl trimethyl ammonium chloride with 0–50 % of 2-aminoethyl methacrylate were prepared by free radical polymerization in various solvents. The polyelectrolytes were characterized by potentiometric titration, NMR, viscometry and size exclusion chromatographic techniques. Polyelectrolyte complex formation between oppositely charged polyelectrolytes with polymer-bound (non)reactive polyelectrolytes was studied in the presence of NaCl and CaCl2 as a function of ionic strength. The physical nature and efficiency of polyelectrolyte complexes that form gels, liquid coacervates, or soluble complexes depend on variables such as ionic strength and charge ratio. The highest complexation efficiency was obtained when a 1:1 charge ratio was used. Liquid coacervates were obtained with high ionic strength NaCl. The inclusion of small amounts of CaCl2 led to drastic property changes in the polyelectrolyte complexes. The divalent calcium ion (Ca2+) displaced the poly[2-(methacryloyloxyethyl) trimethyl ammonium chloride] from the complexes and appeared as a new form of liquid coacervate in a range of ionic strength (50–200 mM CaCl2). The reactivity of the polyelectrolyte system was demonstrated by studying the formation of coacervate complexes. Herein, the feasibility of cross-linking of the resulting coacervate via complementary poly(methacrylic acid-co-2-(methacryloyloxy)ethyl acetoacetate)-bound acetoacetate groups with poly(2-(methacryloyloxy)ethyl trimethyl ammonium chloride-co-2-aminoethyl methacrylate)-bound amine groups is discussed in detail.

Grafted Copolymerization Modification of Hemicellulose Directly in the Alkaline Peroxide Mechanical Pulping (APMP) Effluent and Its Surface Sizing Effects on Corrugated Paper

In this work, the graft copolymerization of acrylamide (AM) and methacryloyloxy ethyl trimethyl ammonium chloride (DMC) with the hemicellulose in the alkaline peroxide mechanical pulping (APMP) effluent was investigated using the Fenton agent (FeSO4/H2O2) as an initiator. The effects of the reaction conditions on the characteristics of the graft copolymers were studied. On the basis of the graft copolymer characterization, the optimum conditions were as follows: total active ingredient concentration 31%, reactive temperature 50 °C, amount of the initiator 0.4%, ratio of H2O2 to FeSO4 1:1, molar ratio of DMC to AM 1.5:20 and optimum percentages of C, G, GE, and viscosity are 65%, 246%, 98%, and 5020 cP, respectively. Structure elucidation of the graft copolymer was obtained by 1H NMR spectroscopy and FT-IR. Gel-permeation chromatography (GPC) was employed to determine the molecular mass and molecular mass distribution of hemicellulose and graft copolymer. The thermal degradation properties of hemicellulose...

Preparation and properties of PEC nanocomposite membranes with carboxymethyl cellulose and modified silica

Carboxymethyl cellulose (CMC)-modified silica nanocomposites were prepared via in situ incorporation of modified silica during the ionic complexation between CMC and poly(2-methacryloyloxy ethyl trimethylammonium chloride) (PDMC). Ionic bonds were introduced between the poly(2-acrylamido-2-methylproanesulfonic acid) modified silica (SiO2-PAMPS) and the polyelectrolyte complex (PEC) matrix. The PEC nanocomposites (PECNs) and their membranes (PECNMs) were characterized with Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile testing. PECNM containing 5wt.% SiO2-PAMPS showed a tensile strength of 68MPa and elongation at break of 7.1%, which were 1.9 and 2.6 times as high as those of pristine PEC membranes, respectively. Moreover, the pervaporation performance of as-prepared PECNMs was evaluated with dehydration of 10wt.% aqueous isopropanol mixtures, and the PECNMs exhibited a flux of 2400gm−2h−1 with a high separation factor of 4491 at 70°C.

Polyelectrolyte complex nanofiltration membranes: performance modulation via casting solution pH

Nanofiltration (NF) membranes were prepared from a solution processable polyelectrolyte complex (PEC) between sodium carboxymethyl cellulose (CMCNa) and poly (2-methacryloyloxy ethyl trimethylammonium chloride) (PDMC).

Measurement of the Electrostatic Interaction between Polyelectrolyte Brush Surfaces by Optical Tweezers

We demonstrated an optical tweezers method to measure the electrostatic interaction between the strong polyelectrolyte brushes, poly(2-(methacryloyloxy)ethyltrimethylammonium chloride) (PMTAC), grafted on silica particles in aqueous media. The weak electrostatic interaction was successfully detected with a resolution of less than 0.1 μN m(-1). The apparent Debye length, including the charge distribution in the polymer brush and the surface potential, decreased as the salt concentration in the medium increased. The experimentally obtained surface charge density was much smaller than that estimated from the amount of polyelectrolyte on the surface. Furthermore, the dissociation of ionic groups was enhanced by decreasing the grafting density of the polyelectrolyte brush. The results suggest that the majority of chloride counterions was immobilized in the dense polyelectrolyte brush layer to neutralize the high charge density.

Surface Modification of Multiwalled Carbon Nanotubes with Engineered Self-Assembled RAFT Diblock Coatings

A facile method to modify the surface of multiwalled carbon nanotubes (MWCNTs) via electrostatic interactions between polyelectrolytes and oxidized MWCNTs was developed. Diblock copolymers containing poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC), a positively charged block, and poly(ethylene glycol) methacrylate (PEGMA), a neutral block, with tailored molecular weights and low polydispersities were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. Acid treated-MWCNTs were coated with the RAFT diblock copolymers to improve their dispersibility in aqueous phosphate buffered saline (PBS) solution. The short positively charged PMETAC block was designed to attach the block copolymers to the surface of MWCNTs via electrostatic interactions, whereas the PEGMA block improved dispersibility of the MWCNTs in aqueous solutions. Extensive screening of the diblock copolymers with different degrees of polymerization (DP) showed that the dispersion stability of the polymer-coated MWCNTs in PBS was greatly improved with increasing chain length of the PEGMA block. In particular, the MWCNTs coated with a diblock copolymer containing PEGMA (DP = 118, the longest block investigated) showed superior dispersion stability in both water and PBS solution.

Use of unmodified SiO2 as nanofiller to improve mechanical properties of polymer-based nanocomposites

SiO2 nanoparticles without surface modification were used to prepare a polymer based nanocomposite: methyl methacrylate (MMA) was selected as the matrix, and copolymerized with a small amount of cationic functional comonomer 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTC). The aim is to improve the dispersion of unmodified SiO2 as well as the interfacial adhesion through electrostatic interaction between the positively charged copolymer matrix and negatively charged fillers, and ultimately to improve the mechanical properties. The chemical structure of P(MMA-co-MTC)/SiO2 was characterized by 1H nuclear magnetic resonance (1H NMR). The interaction between copolymer matrix and SiO2 nanoparticles was investigated by zeta potential and Fourier transform infrared spectroscopy (FT-IR). Meanwhile, the morphologies of the synthesized microspheres were studied by scanning electron microscopy (SEM) and the dispersion of SiO2 nanoparticles in P(MMA-co-MTC)/SiO2 was observed by transmission electron microscopy (TEM). Finally, the mechanical properties of P(MMA-co-MTC)/SiO2 was studied in detail and the tensile fracture surface was studied by SEM. The results indicate that, P(MMA-co-MTC)/SiO2 has been successfully synthesized by in situ suspension copolymerization, and the mechanical properties, especially the flexural property, were remarkably improved due to the better dispersion state and stronger interfacial adhesion ameliorated through electrostatic interaction. When the content of MTC and SiO2 is 10 wt% and 1.0 wt%, respectively, the optimal mechanical properties were obtained: compared to PMMA, the tensile strength was increased by 20.7% and the flexural strength was improved by as much as 140.7%. The whole process does not need surface modification, which makes this method more convenient and less costly.

Preparation and Flocculating Performance of P (AM-DAC-AANa) Copolymer

Amphoteric ionic polyacrylamide P (AM-DAC-AANa) was prepared in aqueous solution using acrylamide (AM), 2-(acryloyloxy) ethyltrimethylammonium chloride (DAC) and sodium acrylate (AANa) as materials by photo assisted initiation. The influences of reaction conditions on intrinsic viscosity and solubility of product were studied. Under the conditions of initiation temperature 20°C, monomer concentration 32%, pH=6 and initiator concentration 0.010%, the intrinsic viscosity and dissolving time of polymer were 13.56dL/g and 66min respectively. Moreover, the flocculating performance of the obtained copolymer was also studied. The results showed that under the conditions of P(AM-DAC-AANa) dosage 0.0250%, intrinsic viscosity 12.13dL·g-1, ionic degree 25%, m (DAC):m (AANa)=1:2, the transmittance of the supernatant, flocculating rate and dewatering rate were 93.90%, 84.47% and 92.41% respectively.

Selective Adsorption of Functionalized Nanoparticles to Patterned Polymer Brush Surfaces and Its Probing with an Optical Trap

The site-specific attachment of nanoparticles is of interest for biomaterials or biosensor applications. Polymer brushes can be used to regulate this adsorption, so the conditions for selective adsorption of phosphonate-functionalized nanoparticles onto micropatterned polymer brushes with different functional groups are optimized. By choosing the strong polyelectrolytes poly(3-sulfopropyl methacrylate), poly(sulfobetaine methacrylate), and poly[2-(methacryloyloxy)ethyl trimethylammonium chloride], it is possible to direct the adsorption of nanoparticles to specific regions of the patterned substrates. A pH-dependent adsorption can be achieved by using the polycarboxylate brush poly(methacrylic acid) (PMAA) as substrate coating. On PMAA brushes, the nanoparticles switch from attachment to the brush regions to attachment to the grooves of a patterned substrate on changing the pH from 3 to 7. In this manner, patterned substrates are realized that assemble nanoparticles in pattern grooves, in polymer brush areas, or substrates that resist the deposition of the nanoparticles. The nanoparticle deposition can be directed in a pH-dependent manner on a weak polyelectrolyte, or is solely charge-dependent on strong polyelectrolytes. These results are correlated with surface potential measurements and show that an optical trap is a versatile method to directly probe interactions between nanoparticles and polymer brushes. A model for these interactions is proposed based on the optical trap measurements.

Fabrication and Characterization of Core–Shell Structured Black Pigment Particles for Electrophoretic Display

To prepare electrophoretic black particles with good suspension stability in the low dielectric medium for the electrophoretic display application, black pigment (B444) as a core material and polystyrene (PS) as a shell material were prepared via dispersion polymerization of styrene, and then the fabricated B444/PS composite particles were positively charged with 2-(methacryloyloxy) ethyl trimethylammonium chloride. Morphology of the B444/PS core-shell particles was observed by scanning electron microscopy, while their chemical structure was confirmed via an FT-IR. Maximum values of the electrophoretic mobility and zeta potential observed by dynamic light scattering reach 4.46 x 10(-6) m2/Vs and 30.23 mV in a low dielectric medium, respectively. The resulting B444/PS particles also showed good electrophoretic movement in the B444/PS particle embedded microcapsules. Therefore, it can be applied in the dual-particle electrophoretic dispersion together with negative charged TiO2, showing black and white images.

Study on the Properties of Wood Polymer Nanocomposites Based on Melamine Formaldehyde-furfuryl Alcohol Copolymer and Modified Clay

A wood polymer nanocomposite was prepared by impregnating a melamine formaldehyde-furfuryl alcohol (MFFA) copolymer, n-methylol acrylamide (NMA), a crosslinking agent, and montmorillonite (MMT) into wood (Ficus hispida) by using a catalyst heat treatment. MMT was modified by using a polymerizable surfactant 2-acryloloxy ethyl trimethyl ammonium chloride (ATAC) and a mixture of surfactants ATAC and cetyl trimethyl ammonium bromide (CTAB) in a molar ratio of 1:1. FTIR and XRD studies confirmed the formation of the MFFA copolymer, NMA, and modification of MMT. These studies also indicated an interaction between wood, polymer, crosslinker, and MMT. Wood treated with modified MMT exhibited lower water uptake, higher dimensional stability, enhanced chemical resistance, thermostability, flame retardancy, and better mechanical properties than wood samples treated with unmodified clay. Samples treated with combined surfactant (ATAC+CTAB) modified clay exhibited better property compared to those samples treated with single surfactant (ATAC) modified clay.

Recent advances in the use of the quartz crystal microbalance with dissipation for the study of the collapse of polyelectrolyte brushes

ABSTRACTThe combination of Quartz Crystal Microbalance and ellipsometry to quantify polyelectrolyte brush hydration and how this impacts on the study of brush collapse is discussed here. Recent articles study collapse after quantifying hydration of poly (2‐methacryloyloxy ethyl trimethyl ammonium chloride) (PMETAC) and poly(potassium sulfo propyl methacrylate). Water lost increases with ionic strength but only a 50% of their water content is lost at 1 M NaCl. For PMETAC brushes the exchange of Cl− by ClO4− is more effective, causing 50% lost at 0.05 M. The hydration and water lost for PMETAC brushes synthesized from thiol monolayers with variable density of initiators from 1 to 100% show that the freely entrapped water of the brushes is around a 10%. Irrespectively of initiator percentage the brush does not lose at 1 M NaCl more than 50% of the original water content. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1068–1072

Barnacle Cement as Surface Anchor for “Clicking” of Antifouling and Antimicrobial Polymer Brushes on Stainless Steel

Barnacle cement (BC) was utilized 'beneficially' as a surface anchor on stainless steel (SS) for coupling of functional polymer brushes via "click" reactions in both "grafting-to" and "grafting-from" processes. Ethylene sulfide (ES), propargyl carbonylimidazole (PPC) and azidoethyl carbonylimidazole (AEC) reacted with amine and/or hydroxyl groups in BC to introduce the corresponding thiol, alkyne, and azide groups on SS surfaces (SS-thiol, SS-alkyne, and SS-azide, respectively). Antifouling zwitterionic SS-PMPC surface was prepared by thiol-ene photopolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) from the SS-thiol surface. Protein-resistant SS-PPEGMA and protein-adsorbing SS-PPFS surfaces were prepared by coupling of the respective azide-functionalized poly(poly(ethylene glycol)methyl ether methacrylate) (azido-PPEGMA) and poly(2,3,4,5,6-pentafluorostyrene) (azido-PPFS) polymer brushes in azide-alkyne "click" reaction. Antifouling alkyne-functionalized poly(N-hydroxyethyl acrylamide) (alkynyl-PHEAA) and antibacterial alkyne-functionalized poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (alkynyl-PMETA) polymer brushes were clicked on the SS-azide surface. Adsorption of bovine serum albumin and bacteria fouling of Gram-negative Escherichia coli ( E. coli ) and Gram-positive Staphylococcus epidermidis ( S. epidermidis ) were investigated on the polymer-functionalized SS surfaces. The versatile bioanchor and functional polymer brush coatings are stable in an abiotic aqueous environment for over a month.

Chain Conformation of Poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] in Aqueous Sodium Chloride Solutions

A series of poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMTAC) in aqueous NaCl solutions with a weight-average molecular weight (Mw) of between 6.0 × 103 and 1.5 × 105 were characterized by synchrotron radiation small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements at 298 K. The hydrodynamic radius (RH) of PMTAC initially decreased with increasing salt concentration (Cs) and then leveled off at Cs = 0.5–1.0 M. The values of z-average root-mean-square radius of gyration (⟨S2⟩z1/2) simply increased with a decrease in Cs for Mw > 2 × 104 g/mol. In contrast, the values of ⟨S2⟩z1/2 for Mw < 2 × 104 g/mol increased with an increase in Cs probably because of a change in local conformation of PMTAC chain. To study local chain conformation of PMTAC, scattering functions and Mw dependences of ⟨S2⟩z1/2 and RH for PMTAC were analyzed in terms of the helical wormlike chain (HW) model which is a simple continuous elastic wire model with bending and torsional energies. The cha...

Improved antifouling properties of PVDF membranes modified with oppositely charged copolymer

Biofouling resulting from the attachment of microorganisms communities to the membrane surface is the major obstacle for the widespread application of membrane technology. This work develops a feasible approach to prepare an anti-biofouling poly(vinylidene fluoride) (PVDF) membrane. A copolymer that possessed oppositely charged groups was first synthesized via radical copolymerization with methyl methacrylate, 2-methacryloxy ethyltrimethyl ammonium chloride and 2-acrylamide-2-methyl propane sulphonic acid as monomers. The copolymer was blended with the PVDF powder to prepare the antifouling membrane via the immersed phase inversion method. The antifouling properties of the modified PVDF membrane were studied by X-ray photoelectron spectroscopy, field emission scanning electron microscopy, water contact angle measurement, zeta-potential measurement, protein adsorption, microbial adhesion and filtration experiments. The modified PVDF membrane showed limited adsorption and adhesion of protein bovine serum albumin and microbes (Escherichia coli and Saccharomyces cerevisiae) with increasing copolymer concentration in the casting solution. The modified PVDF membrane exhibited excellent antibiofouling properties.

Preparation and Characterization of Natural Rubber/Poly [Styrene-co-2-(Methacryloyloxy) Ethyl Trimethylammonium Chloride] Nanocomposites by Heterocoagulation

The simple technique as heterocoagulation was used to prepare natural rubber (NR) with poly[styrene-co-2- (methacryloyloxy) ethyl trimethylammonium chloride] (P(S-QDM)) nanocomposites (NR/P(S-QDM)). P(S-QDM) particle was prepared by emulsion polymerization at 80°C using azobisisobutylamide dihydrochloride as initiator. Under the alkaline condition, NR latex (NRL) surface represents negative charge deriving from protein adsorbed on its surface while strong positive charge of P(S-QDM) surface deriving from QDM structure is obtained. The assembly via electrostatic interaction between NRL and P(S-QDM) particles in the emulsion state is then taken place with pH adjustable from 2 to 8. The particle surface, particle size and charge of the polymer nanocomposites were measured by scanning electron microscope, dynamic light scattering and zeta potential, respectively, to compare those with the original NR properties.

The surface charge of anti-bacterial coatings alters motility and biofilm architecture.

Bacterial biofilms affect many areas of human activity including food processing, transportation, public infrastructure, and most importantly healthcare. This study addresses the prevention of biofilms and shows that the surface charge of an abiotic substrate influences bacterial motility as well as the morphology and physiology of the biofilm. Grafting-from polymerisation was used to create polymer brush surfaces with different characteristics, and the development of Pseudomonas aeruginosa biofilms was followed using confocal microscopy. Interestingly, two types of biofilms developed on these surfaces: mushroom structures with high levels of cyclic diguanylate (c-di-GMP) were found on negatively charged poly (3-sulphopropylmethacrylate) (SPM) and zwitterionic poly (2-(methacryloyloxy)ethyl)dimethyl-3-sulphoproyl) ammonium hydroxide) (MEDSAH), while flat biofilms developed on glass, positively charged poly (2-(methacryloyloxy)-ethyl trimethyl ammonium chloride) (METAC), protein-repellent poly oligo(ethylene glycol methyl ether methacrylate) (POEGMA) and hydrophobic polymethylmethacrylate (PMMA). The results show that of all the surfaces studied, overall the negatively charged polymer brushes were most efficient in reducing bacterial adhesion and biofilm formation. However, the increased level of regulatory c-di-GMP in mushroom structures suggests that bacteria are capable of a quick physiological response when exposed to surfaces with varying physicochemical characteristics enabling some bacterial colonization also on negatively charged surfaces.

A polyion complex micelle with heparin for growth factor delivery and uptake into cells

Cationic polymers are promising materials for the controlled delivery of heparin allowing the therapeutic delivery of growth factors bound to heparin. In this study, a series of block copolymers were prepared from oligo(ethylene glycol) methyl ether methacrylate (OEGMEMA) and 2-(methacryloyloxy)ethyl trimethyl ammonium chloride (METEA) via reversible addition-fragmentation chain transfer (RAFT) polymerization by varying the cationic block (METEA) from 5 to 54 units. Polyion complexes micelles between these block copolymers and heparin were formed. Their size could be systematically varied between 5 and 55 nm in size as well as -20 to +10 mV in overall charge by changing the cationic block length as well as the ratio of polymer to heparin. The polymer/heparin complexes did not impair the proliferation of human colon carcinoma cell line, WiDr, compared to cells exposed to medium only. The size of the cationic block copolymer as well as the ratio in which it was complexed with heparin influenced both heparin biological activity in a BaF32 cell assay as well as uptake into WiDr cells as determined by flow cytometry which demonstrated that the properties of the block copolymers can be tuned for various applications.

Stainless steel surfaces with thiol-terminated hyperbranched polymers for functionalization via thiol-based chemistry

Hyperbranched polyethyleneimine (BPEI) was coupled to a polydopamine-coated stainless steel (SS) substrate. Subsequent mercaptoethylation of BPEI with ethylene sulfide produced thiol functional groups on the SS surface. Functionalization of the surface was achieved by end-capping of the hyperbranches with organic molecules via thiol-based chemistry, including thiol–epoxy coupling, thiol–ene radical photo-addition and thiol–Michael addition. The SS-P(HEMA-b-SBMA) surface was prepared via thiol–ene radical photo-addition of the hyperbranches with an alkene-functionalized poly(2-hydroxyethyl methacrylate) (alkene-PHEMA) from atom transfer radical polymerization (ATRP) and subsequent block copolymerization of the zwitterionic monomer, N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethyl ammonium betaine (SBMA). The SS-PPEGMA and SS-PMETA surfaces were prepared, respectively, by thiol-initiated photopolymerization of poly(ethylene glycol)methyl ether methacrylate (PEGMA) and 2-(methacryloyloxy)ethyl trimethylammonium chloride (META). The antifouling SS-P(HEMA-b-SBMA) and SS-PPEGMA surfaces exhibit resistance to bacterial adhesion, while the SS-PMETA surface is bactericidal. Metal surfaces with thiol-terminated hyperbranches thus provide a versatile platform for tailoring surface functionalities.