Nitroxide-Mediated Polymerization of 2-(Diethylamino)ethyl Methacrylate (DEAEMA) in Water

Abstract

Nitroxide-mediated polymerization (NMP) of 2-(diethylamino)ethyl methacrylate (DEAEMA) with a small amount of acrylonitrile (AN) as a comonomer was performed for the first time in water at 90°C and atmospheric pressure using n-hydroxysuccinimidyl BlocBuilder (NHS-BB) alkoxyamine without addition of excess nitroxide. The same reaction was carried out using the bicomponent initiating system composed of 2,2′-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (VA-044) as initiator and N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (SG1) as nitroxide. Both polymerization reactions were well-controlled and exhibited excellent livingness as evidenced by low molar dispersity and evolution of the molar mass distribution. The hydrolytic stability of DEAEMA at the polymerization conditions and the effects of several parameters including initiating system, temperature, ratio of nitroxide to initiator, initiator and monomer concentrations, and comonomer type were investigated. Chain extension of the synthesized macroinitiator with methyl methacrylate (MMA) and styrene (S) in a one-pot process led to the in situ formation of poly(DEAEMA-co-S)-b-poly(MMA-co-S) diblock copolymers based on the polymerization-induced self-assembly (PISA) process. ■ INTRODUCTIONDevelopment of controlled/living radical polymerization (LRP) has had a major impact on polymer science. 1−3 (The new terminology of reversible deactivation radical polymerization (RDRP) has been proposed by IUPAC for LRP. 4 ) Polymeric architectures with different composition, structures, and functionalities can be prepared in relatively mild conditions by LRP techniques. Of the three main types of LRPs, nitroxidemediated polymerization (NMP) and atom-transfer radical polymerization (ATRP) are based on reversible activation− deactivation cycles of growing polymer chains while reversible addition−fragmentation transfer (RAFT) polymerization is based on reversible chain transfer. 3 NMP is a powerful technique with arguably the simplest mechanisms among all LRP techniques for preparing polymers with a narrow molecular weight distribution (MWD) and low molar dispersity (Đ). 5 Furthermore, there is no concern of residual catalyst, color, or toxicity in the final polymer. LRP can be applied for the preparation of well-defined polymeric architectures in aqueous media which is not possible in ionic polymerization. 1 However, applying LRP in aqueous media (homogeneous or dispersed) is often quite difficult due to problems such as hydrolysis and aminolysis reactions in RAFT polymerization or other side reactions in the case of ATRP. 6,7 There are a very limited number of reports related to NMP in homogeneous aqueous solution. A further difficulty for NMP is the high temperature (>100°C) traditionally required which necessitates using pressurized vessels. However, performing NMP at lower temperatures now is possible with some nitroxide/ monomer combinations. The first example of NMP conducted in homogeneous aqueous solution was with of sodium 4-styrenesulfonate in ...

Poly(methacrylic acid-ran-2-vinylpyridine) Statistical Copolymer and Derived Dual pH-Temperature Responsive Block Copolymers by Nitroxide-Mediated Polymerization

“…It should be noted here that additional free nitroxide was not required to control the methacrylate-rich compositions. The same behavior has been seen with other methacrylate-rich compositions [51,58,67] and with a butyl acrylate homopolymerization [64] mediated by NHS-BlocBuilder, which simplifies the formulation, in addition to potentially adding another functional group for coupling other chains [58], although this was not applied here. Furthermore, the tBMA/2VP copolymers had final copolymer compositions very close to the initial compositions, suggesting that the copolymerization was polymerizing in essentially a random fashion.…”

CO2-responsive polymeric materials: synthesis, self-assembly, and functional applications

“…In emulsion polymerization, the amount of surfactant has a direct effect on the particle size and rate of reaction. 61 DMAEMA is another 70 While these two monomers are prone to hydrolysis, 133 based on our observations, at similar conditions of pH and temperature, DEAEMA is more resistant to hydrolysis than DMAEMA. The particle size and solids content are both important for end-use properties.…”

“…However, since the reaction temperature was relatively high (70 1C), most of the imidazole groups created from initiator decomposition were likely in their neutral form. 133 CO 2 -switchable dextran-graft-poly((N-amidino)hexyl methacrylamide), (Dex-g-PAHMA), copolymers were prepared by FRP. The produced latex was coagulatable and redispersible with removal and addition of CO 2 , respectively.…”

Polymerization induced self-assembly: tuning of morphology using ionic strength and pH

“…Cunningham and coworkers have reported the use of DEAEMA as solvophilic block in NMP emulsion polymerization exploiting in situ formed amphiphilic block copolymer self-assembly as nucleation mechanism to generate spherical particles. [44][45][46] Lansalot and Carlmark 38 conducted RAFT emulsion polymerization based on the PISA process to obtain spherical particles comprising P(DMAEMA-stat-MAA)-b-PMMA, and Armes and coworkers reported synthesis of spherical particles of poly(2-(dimethylamino)ethyl methacrylate-b-stearyl methacrylate) (PDMAEMA-b-PSMA) via RAFT dispersion polymerization in ethanol. 37 Despite the potential of tuning the charge density of P(DMAEMA) by adjustment of the pH, to the best of our knowledge there are no precedents of exploiting this property to tune the PISA particle morphology beyond spherical particles.…”