Target grafting of poly(2-(dimethylamino)ethyl methacrylate) to biodegradable block copolymers

A series of copolymers composed of methoxy poly(ethylene glycol) and a hydrophobic block of poly(ɛ-caprolactone-co-propargyl carbonate) grafted with poly(2-[dimethylamino]ethyl methacrylate) was synthesized by combining ring opening polymerization, azide-alkyne click reaction, and atom transfer radical polymerization (ATRP). Well-defined copolymers with a target composition and a tailored structure were achieved via the grafting from approach by using a single catalytic system for both click reaction and ATRP. Kinetic studies demonstrated the controlled/living character of the employed polymerization methods. The thermal properties and self-assembly in aqueous medium of the graft copolymers were dependent on their composition. The resulting polymeric materials showed low cytotoxicity toward L929 cells, demonstrating their potential for biomedical applications. This type of materials containing cationic side chains tethered to biocompatible and biodegradable segments could be the basis for promising candidates as drug and gene delivery systems.     

Microwave-Assisted Synthesis and Characterization of Poly(2-(dimethylamino)ethyl methacrylate) Grafted Gellan Gum

Poly(2-(dimethylamino)ethylmethacrylate) was grafted on gellan gum (GG) in aqueous medium under microwave irradiation using ammonium persulfate and N,N,N′N′-tetramethylethylenediamine as the initiation system. Grafted copolymers were characterized by FT-IR, TGA, and SEM techniques. The influence of microwave power, exposure time, and composition of the reaction mixture on extent of grafting was studied. Conditions for obtaining the highest degree of grafting were optimized. The rate of grafting was determined from weight measurements. The overall activation energy for grafting is found to be 31.2 kJ/mol, indicating the occurrence of the grafting process with absorption of low thermal energy.     

Lanthanocene amide complexes as single‐component initiators for the polymerization of (dimethylamino)ethyl methacrylate

Polymerization of (dimethylamino)ethyl methacrylate (DMAEMA) by lanthanocene amide complexes was investigated. The results show that (MeC₅H₄)₂LnN(i‐Pr)₂[tetrahydrofuran (THF)] (Ln = Y, Er, Yb), (MeC₅H₄)₂YbNC₅H₁₀(HNC₅H₁₀) (HNC₅H₁₀ = piperidine), (MeC₅H₄)₂YbNPh₂(THF), and (t‐BuC₅H₄)₂YbNPh₂(THF) are effective initiators for the polymerization of DMAEMA, and the molecular weights of the polymers obtained exceed 100 × 10³. The polymerization reactions can be varied over quite a broad range of temperatures from ?78 to 40 °C. The central metals and amido groups had a significant effect on the polymerization activity. The increasing activity of central metals and amido groups was Yb < Er < Y and NPh₂ < N(i‐Pr)₂ < NC₅H₁₀, respectively. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 612–616, 2002; DOI 10.1002/pola.10141     

Statistical copolymers of N‐vinylpyrrolidone and 2‐(dimethylamino)ethyl methacrylate via RAFT: Monomer reactivity ratios,thermal properties,and kinetics of thermal decomposition

Statistical copolymers of N‐vinylpyrrolidone (NVP) with 2‐(dimethylamino)ethyl methacrylate (DMAEMA) were prepared by Reversible Addition‐Fragmentation chain Transfer Polymerization (RAFT), employing three different RAFT agents: [(O‐ethylxanthyl)methyl]benzene, [1‐(O‐ethylxanthyl)ethyl]benzene, and O‐ethyl S‐(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman‐Ross, inverted Fineman‐Ross, Kelen‐Tüdos, and extended Kelen‐Tüdos graphical methods, along with the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length. All the methods indicate that the DMAEMA reactivity ratio is much greater than the one of NVP, thus, the statistical copolymers are in fact pseudo‐diblocks. The glass‐transition temperature (T_g) values of the copolymers were measured by Differential Scanning Calorimetry. Furthermore, a systematic and detailed investigation has been done, on the thermal degradation of the copolymers compared with the respective homopolymers, by Thermogravimetric Analysis, within the framework of the Ozawa‐Flynn‐Wall and Kissinger methodologies. Apparently, the thermal stability of the copolymers is influenced by both monomers and by the structure of the thiocarbonylthio end groups due to the RAFT agents. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3776–3787     

Synthesis and characterization of original 2-(dimethylamino)ethyl methacrylate/poly(ethyleneglycol) star-copolymers

Novel synthetic transfection vectors with linear triblock and star-shaped diblock copolymer architectures have been synthesized by atom transfer radical polymerization (ATRP). Based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) and copolymerization with poly(ethyleneglycol) α-methoxy, ω-methacrylate (MAPEG), the synthesis was realized using CuBr ligated with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as catalytic complex and either ethyl 2-bromoisobutyrate (EBⁱB) or bis(α-bromoisobutyryl) N-methyl diethanolamine (DEA) or tris(α-bromoisobutyryl) triethanolamine (TEA) as (multifunctional)initiator. The polymers were characterized by GPC and NMR. The solution properties of these homopolymers and palm-tree-like copolymers were investigated by viscometry either in pure water or in buffered aqueous solutions. Interestingly, all the synthesized polymers show polyelectrolyte effect in Millipore water (25 °C) and in Hepes (20 mM) buffer solution (pH 7.4, NaCl 155 mM, 25 °C). Fitting of these viscometric data according to either Fuoss or Fedors equation allows for calculating the intrinsic viscosity of the polymers. These results are compared with dynamic light scattering (DLS) experiments to determine absolute masses. Finally, DEA based palm-tree-like copolymer is investigated to AFM measurement and micelles were observed at pH 8.     

Synthesis and characterization of amphiphilic star copolymers of 2-(dimethylamino)ethyl methacrylate and methyl methacrylate: Effects of architecture and composition

Six amphiphilic star copolymers comprising hydrophilic units of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and hydrophobic units of methyl methacrylate (MMA) were prepared by the sequential group transfer polymerization (GTP) of the two comonomers and ethylene glycol dimethacrylate (EGDMA) cross-linker. Four star-block copolymers of different compositions, one miktoarm star, and one statistical copolymer star were synthesized. The molecular weights (MWs) and MW distributions of all the star copolymers and their linear homopolymer and copolymer precursors were characterized by gel permeation chromatography (GPC), while the compositions of the stars were determined by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Tetrahydrofuran (THF) solutions of all the star copolymers were characterized by static light scattering to determine the absolute weight-average MW () and the number of arms of the stars. The of the stars ranged between 359,000 and 565,000 g mol⁻¹, while their number of arms ranged between 39 and 120. The star copolymers were soluble in acidic water at pH 4 giving transparent or slightly opaque solutions, with the exception of the very hydrophobic DMAEMA₁₀-b-MMA₃₀-star, which gave a very opaque solution. Only the random copolymer star was completely dispersed in neutral water, giving a very opaque solution. The effective pKs of the copolymer stars were determined by hydrogen ion titration and were found to be in the range 6.5-7.6. The pHs of precipitation of the star copolymer solutions/dispersions were found to be between 8.8-10.1, except for the most hydrophobic DMAEMA_10-b-MMA₃₀-star, which gave a very opaque solution over the whole pH range.     

Controlled polymerization of 2‐(diethylamino)ethyl methacrylate and its block copolymer with N‐isopropylacrylamide by RAFT polymerization

Poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) homopolymers with low polydispersities were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization. The performances of two chain transfer agents, 2‐cyanoprop‐2‐yl dithiobenzoate and 4‐cyanopentanic acid dithiobenzoate (CPADB), were compared. It was found that the polymerization of 2‐(diethylamino) ethyl methylacrylate was under good control in the presence of CPADB with 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) as initiator in 1,4‐dioxane at 70 °C. The kinetic behaviors were investigated under different CPADB/ACPA molar ratios. A long polymerization inhibition period was observed at high [CPADB]/[ACPA] ratio. The influences of [CPADB]/[ACPA] ratio, monomer/[CPADB] ratio, and temperature were studied with respect to monomer conversion, molecular weight control, and polydispersity index (PDI). The PDI decreased from 1.21 to 1.12, as the CPADB/ACPA molar ratio changed from 2 to 10. The molecular weight of PDEAEMA could be controlled by monomer/CPADB molar ratio. The control over MW and PDI was improved as the temperature increased from 60 to 70 °C; however, an additional increase to 80 °C led to a loss of control. Using PDEAEMA macroRAFT agent, pH/thermo double‐responsive block copolymers of PDEAEMA and poly(N‐isopropylacrylamide) (PDEAEMA‐b‐PNIPAM) with narrow polydispersity (PDI, 1.24) were synthesized. The lower critical solution temperature of PDEAEMA‐b‐PNIPAM block copolymer depended on the environmental pH. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3294–3305, 2008     

Poly(2-(dimethylamino)ethyl methacrylate)-b-poly(hydroxypropyl methacrylate) copolymers/bovine serum albumin complexes in aqueous solutions

Complexation ability of poly(2-(dimethylamino)ethyl methacrylate)-b-poly(hydroxy propyl methacrylate) (PDMAEMA-b-PHPMA) amphiphilic doubly thermo-responsive block copolymers, and their quaternized counterparts QPDMAEMA-b-PHPMA, toward bovine serum albumin (BSA) is studied in aqueous solutions. The PDMAEMA-b-PHPMA amphiphilic block copolymers self-assemble in nanostructured aggregates with PDMAEMA coronas having different inner structure and micro-polarity depending on the solubilization protocol utilized when inserted in aqueous media. By incorporating different BSA concentrations, we investigate the copolymer–protein interactions by light scattering measurements in aqueous solutions in a broad temperature range, utilizing different solubilization protocols for the copolymers. Fluorescence spectroscopy and ζ-potential measurements were also utilized to investigate the structure and properties of the copolymer/protein complexes formed in each case. Such knowledge may lead to a better understanding of the inner structure and micro polarity of the nanostructured aggregates formed by the novel (Q)PDMAEMA-b-PHPMA copolymers, along with their potential abilities in nanocarrier formation, protein complexation, stabilization, and delivery.     

Solution properties of well-defined 2-(dimethylamino)ethyl methacrylate-based (co)polymers: A viscometric approach

Well-defined poly(2-(dimethylamino)ethyl methacrylate)-based (co)polymers with various molar masses were synthesized by atom transfer radical polymerization (ATRP) using CuBr ligated with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as catalyst, and ethyl 2-bromoisobutyrate (EBiB) or α-methyl, ω-(2-bromoisobutyrate) poly(ethylene glycol) (mPEG_x-BiB) as (macro)initiator. The solution properties of these (co)polymers were investigated by viscometry either in pure water or in concentrated buffer solutions. It comes out that reduced viscosity in pure water is strongly affected by the molar mass of poly(2-(dimethylamino)ethyl methacrylate) block but also by the quaternization degree of tertiary amino groups. In fact, a polyelectrolyte effect can only be detected when the charge density per macromolecule reaches a critical value either in terms of molar mass or quaternization degree. Fitting of viscometry data according to either Huggins or Fuoss and Fedors equation also allows calculating the intrinsic viscosity and approaching the overlap concentration.     

聚[2-(4-苯基偶氮苯氧基)乙基丙烯酸酯]的合成及光响应性能研究

从4-羟基偶氮苯出发,依次与2-氯乙醇、丙烯酰氯反应,合成了2-(4-苯基偶氮苯氧基)乙基丙烯酸酯(PAPEA)。接着以PAPEA为单体,二硫代苯甲酸异丁腈酯(CPDB)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,利用可逆加成-断裂链转移(RAFT)聚合法合成了聚[2-(4-苯基偶氮苯氧基)乙基丙烯酸酯](PPAPEA)均聚物,同时考察了反应时间、引发剂和链转移剂浓度等因素对聚合反应的影响。利用FT-IR、1H-NMR和GPC等对单体和聚合物的结构进行了表征,并利用UV对聚合物的光响应性能进行了测试。结果表明,PAPEA的聚合反应动力学曲线呈良好的线性关系,分子量分布较窄(小于1.3);均聚物在紫外光照下的异构化速率随分子量的增大而减缓,而其在自然光下的回复速率变化不大。     

2-vinyloxy ethyl phthalimide polymerization initiated by 1-(isobutoxy) ethyl acetate in the presence of ethyl aluminum dichloride and either ethyl acetate or ethyl benzoate

2-Vinyloxy ethyl phthalimide (ImVE) was polymerized using 1-(isobutoxy) ethyl acetate as the initiator in the presence of ethyl aluminum dichloride and either ethyl acetate or ethyl benzoate. The resulting polymers have a narrow molecular weight distribution, and their molecular weight can be controlled within a narrow range by varying the monomer and initiator concentrations. Diblock copolymers with n-butyl vinyl ether can also be formed. The behavior of the polymerization is consistent with a living cationic mechanism. A brief comparison of the title system with other initiating systems is also presented. © 1996 John Wiley & Sons, Inc.     

RAFT Inverse Microemulsion Polymerization: Effects of Monomer Solubility and Different Types of Initiators

The effects of monomer solubility and different types of initiators are for the first time reported for a reversible addition–fragmentation chain transfer (RAFT) inverse microemulsion polymerization system. 2‐(dimethylamino)ethyl methacrylate is selected as monomer due to its solubility in several solvents. A nonionic surfactant, cyclohexane, and a trithiocarbonyl RAFT chain transfer agent (CTA) are also used as main components. The reactions are performed adjusting the dispersed aqueous phase with selected pH values (5, 7, and 10), using an oil‐soluble or a water‐soluble initiator. In this microemulsion system, the RAFT process is especially influenced by the mono­mer content in the dispersed aqueous phase, directly related to the final pH. It is suggested that monomer diffusion and changes in the monomer/CTA ratio at the polymerization loci are the primary reasons for the different behaviors observed, specially those related to the molar mass properties.

     

Dispersion polymerization of styrene in carbon dioxide stabilized by copolymers of poly(propylene glycol) methacrylate and 2‐(perfluorooctyl)ethyl methacrylate

The dispersion polymerization of styrene in carbon dioxide with a series of copolymers of poly(propylene glycol) methacrylate (PPGMA) and 2‐(perfluorooctyl)ethyl methacrylate (FOEMA) as the polymerization dispersants was examined. It was demonstrated that PPGMA and FOEMA copolymers and polymers containing 52–100% FOEMA could be used as effective dispersants for the polymerization, and the composition of the copolymeric dispersant had a dramatic effect on both the polymerization yield and the morphology of the resulting polystyrene. The effects of the concentrations of the copolymeric dispersants, the concentrations of the monomer, and the reaction pressure were also investigated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3804–3815, 2003     

Superhydrophobic surfaces of microspheres obtained by self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-<Emphasis Type="Italic">ran</Emphasis>-2-(dimethylamino)ethyl acrylate] in supercritical carbon dioxide

Superhydrophobic surfaces were obtained by coating with microspheres formed by the self-assembly of poly[2-(perfluorooctyl)ethyl acrylate-ran-2-(dimethylamino)ethyl acrylate] (P[POA-r-DAA]) in the presence of dicarboxylic acids in supercritical carbon dioxide. The P[POA-r-DAA] random copolymer aggregated into micellar microspheres through the hydrogen bond cross-linking of the amino groups via the carboxylic acids. The size of the microspheres and the amount of the acids needed to produce them were dependent on the kinds of acids. Glutaric acid (Glu) and perfluorosuccinic acid (Psuc) provided microspheres at a 0.5 molar ratio of the acid/DAA. Psuc produced smaller microspheres than Glu. Maleic acid (Ma), succinic acid (Suc), and azelaic acid (Az) required a higher molar ratio to produce the microspheres. These acids provided spherical particles at the ratio of 1.0. The microspheres produced by Suc and Az contained particles with a several hundred nanometer size. The surface coated with the microspheres showed high water contact angles of 164°–172°.

Thermal and pH dual responsive polyurethane/2-(diisopropylamino)ethyl methacrylate hybrids: Synthesis,characterization, and swelling behavior

This article describes the synthesis and characterization of stimuli-sensitive hybrid films using 2-(diisopropylamino)ethyl methacrylate (DPA), and a polyurethane (PU) base on isophorone diisocyanate. Hybrid films with different amounts of DPA present good film and physicochemical properties. Characterization techniques such as Fourier transform infrared, UV–visible, modulate differential scanning calorimetry, and thermogravimetric analysis reveal chemical interactions between PU and DPA groups. Swelling behavior of films shows a dependence on DPA content, pH, and temperature and different mechanisms of water uptake in response to pH and temperature variations. Hybrid systems would allow controlling water absorption not only through pH or temperature but also from the chosen PU/DPA proportion.     

Synthesis of Comblike Poly（methyl methacrylate） by Atom Transfer Radical Polymerization with Poly（ethyl 2-bromoacrylate） as Macroinitiator

Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and ^1H NMR.     

Copolymerizations of butyl methacrylate and fluorinated methacrylates via RAFT miniemulsion polymerization

Copolymerizations of n‐butyl methacrylate (BMA) and fluoro‐methacrylates (including 2,2,3,4,4,4‐hexafluorobutyl methacrylate, HFBMA and 2,2,2‐trifluoroethyl methacrylate, TFEMA) were carried out via reversible addition‐fragmentation chain transfer miniemulsion polymerization, using cumyl dithiobenzoate as a chain transfer agent. The experimental results show that the copolymerizations exhibit “living” fashion, with controlled molecular weights and narrow polydispersities. The reactivity ratios of BMA and fluoromethacrylate in this kind of polymerization system were investigated by size exclusion chromatography and nuclear magnetic resonance, from which the Q‐ and e‐values of HFBMA and TFEMA were calculated. Compared with its corresponding non‐fluoric methacrylate, fluorinated methacrylate exhibits higher resonance stability of the radical adducts. The Q‐value of fluorinated methacrylate is higher (Q_BMA = 0.82 to Q_HFBMA = 1.70 and Q_EMA = 0.76 to Q_TFEMA = 1.01), and e‐value is much larger (e_BMA = 0.28 to e_HFBMA = 1.24 to and e_EMA = 0.17 to e_TFEMA = 1.29) for its rather unique high electron‐withdrawing inductive effect of the fluoroalkyl ester group. The thermal property and the wetting property of copolymers were also discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5067–5075, 2007     

Preparation,characterization and thermal stability of poly[2-(Dimethylamino)ethyl acrylate]

Poly[2-(dimethylamino)ethyl acrylate] (PDAEA) and polymer complexes of 2-(dimethylamino)ethyl acrylate (DAEA) with nickel(II), copper(II), iron(III) and cobalt(II) chlorides were prepared and characterized by means of IR, electronic spectra and elemental analysis. The thermal stability of the homopolymer was compared with those of the polymer complexes, and the order of stability was given. The activation energies of the polymer complexes were calculated.