2-(Dimethylamino)ethyl Acrylate: Properties & Applications

2-(Dimethylamino)ethyl acrylate is a tertiary-amine-functionalized acrylate monomer widely employed in the synthesis of stimuli-responsive, cationic, and amphiphilic polymers for applications ranging from gene delivery vectors to water-treatment flocculants.

CAS Number

2439-35-2

Molecular Formula

C7H13NO2

Molecular Weight

143.18 g/mol

Appearance

Colorless to pale yellow liquid

Key Functional Groups

Tertiary amine, acrylate ester (vinyl double bond)

Polymerization Methods

Free-radical, RAFT, ATRP, NMP

Primary Application Areas

Gene delivery, flocculants, coatings, stimuli-responsive hydrogels

Chemical Identity and Physical Properties

2-(Dimethylamino)ethyl acrylate (DMAEA, CAS 2439-35-2) is the acrylate ester of 2-(dimethylamino)ethanol. Its molecular formula is C₇H₁₃NO₂ with a molecular weight of 143.18 g/mol. The compound bears two key functional groups: a reactive vinyl double bond derived from the acrylate moiety and a tertiary amine nitrogen that confers pH-responsiveness and the capacity for quaternization.

At ambient conditions, DMAEA is a colorless to pale yellow liquid with a characteristic amine odor. It is miscible with common organic solvents and partially miscible with water. The tertiary amine group (pK_a of the conjugate acid approximately 8–9) enables protonation under mildly acidic conditions, making polymers derived from DMAEA intrinsically pH-sensitive. Inhibitor is typically added to the commercial material to prevent premature polymerization during storage; inhibitor removal by distillation or alumina filtration is recommended before use.

Polymerization Chemistry and Synthetic Strategies

DMAEA undergoes radical polymerization readily due to the electron-donating nature of the dimethylamino group activating the acrylate double bond. It is compatible with conventional free-radical polymerization as well as controlled/living radical techniques, including Reversible Addition–Fragmentation Chain-Transfer (RAFT) polymerization, Atom Transfer Radical Polymerization (ATRP), and Nitroxide-Mediated Polymerization (NMP). Controlled methods allow precise tuning of molecular weight, dispersity, and architecture (block, star, or gradient copolymers).

DMAEA copolymerizes well with a broad range of comonomers such as acrylamide, methyl acrylate, styrene, and N-isopropylacrylamide (NIPAM). Post-polymerization quaternization with alkyl halides (e.g., methyl iodide or benzyl chloride) converts the tertiary amine repeat units into permanent cationic quaternary ammonium groups, substantially increasing water solubility and enabling electrostatic interaction with negatively charged substrates such as DNA and cell membranes.

Research Applications

Gene and Drug Delivery: Poly(DMAEA) and its quaternized derivatives form polyplexes with plasmid DNA and siRNA via electrostatic condensation, making them candidate non-viral transfection agents. The pH-responsive behavior of non-quaternized poly(DMAEA) facilitates endosomal escape, a critical step in intracellular delivery.

Stimuli-Responsive Hydrogels and Coatings: Copolymerization of DMAEA with NIPAM or other thermoresponsive monomers yields dual-responsive (pH and temperature) hydrogels suitable for controlled-release applications and smart-surface coatings.

Water Treatment and Flocculation: Cationic copolymers incorporating DMAEA or its quaternized form are employed as flocculants for the removal of anionic contaminants and suspended particles from wastewater streams.

Antifouling and Antimicrobial Coatings: Quaternized poly(DMAEA) brushes grafted onto surfaces exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria by disrupting bacterial membranes, offering a route to contact-active antimicrobial surfaces.

Handling, Storage, and Safety Considerations

DMAEA is a reactive acrylate monomer and should be treated with appropriate caution. It is classified as a flammable liquid; keep away from heat, sparks, and open flames. The compound is corrosive and irritating to skin, eyes, and the respiratory tract—use nitrile gloves, safety goggles, and work in a well-ventilated fume hood. Inhalation of vapor should be avoided.

Store in a tightly sealed container in a cool, dry, well-ventilated area away from light and heat sources. The inhibitor present in the commercial product retards spontaneous polymerization; do not store the monomer after inhibitor removal for extended periods. Recommended storage temperature is typically 2–8 °C under an inert atmosphere for long-term stability. Consult the product Safety Data Sheet (SDS) for full hazard classification, first-aid measures, and disposal guidance before use.

Reagent Quality and Selection Guide

When selecting DMAEA for research use, purity grade is a primary consideration. High-purity grades (≥97–99%) are recommended for controlled polymerization experiments (RAFT, ATRP) where trace impurities can poison the catalyst system or chain-transfer agent, leading to poor molecular weight control and broad dispersity. For less demanding free-radical polymerizations, technical-grade material may be sufficient.

Inhibitor content should be confirmed from the certificate of analysis (CoA); common inhibitors include monomethyl ether hydroquinone (MEHQ) or phenothiazine. Freshness is important—check the lot date and ensure the monomer has been stored under recommended conditions to avoid partial polymerization. Aladdin Scientific offers DMAEA (SKU: D102735) with documented purity and CoA available upon request, suitable for a wide range of polymer chemistry research applications.

Frequently asked questions

What is the difference between 2-(Dimethylamino)ethyl acrylate (DMAEA) and 2-(Dimethylamino)ethyl methacrylate (DMAEMA)?

DMAEA contains an acrylate group (no alpha-methyl substituent), making it more reactive in radical polymerization than DMAEMA, which carries an additional methyl group on the alpha-carbon. This higher reactivity of DMAEA can be advantageous for faster polymerization but may also require more careful handling to prevent premature gelation. The resulting polymers differ in glass transition temperature, hydrolytic stability, and chain flexibility.

How do I remove the inhibitor from DMAEA before polymerization?

The inhibitor (typically MEHQ or phenothiazine) can be removed by passing the monomer through a column of activated basic alumina under an inert atmosphere, or by vacuum distillation. The purified monomer should be used promptly or stored at low temperature under inert gas to prevent uninhibited polymerization. Always confirm inhibitor removal is complete via UV-Vis spectrophotometry or inhibitor test strips where applicable.

Can DMAEA be used directly in RAFT or ATRP polymerization?

Yes, DMAEA is compatible with both RAFT and ATRP; however, the tertiary amine group can coordinate with copper catalysts used in ATRP, potentially affecting catalyst activity and polymerization control. Careful selection of ligand and copper loading, or use of RAFT with a suitable chain-transfer agent, is recommended. Deoxygenation of the reaction mixture by freeze-pump-thaw cycles or sparging with inert gas is essential for successful controlled polymerization.

Is poly(DMAEA) cytotoxic, and is it suitable for biological applications?

Cationic polymers derived from DMAEA, particularly after quaternization, can exhibit cytotoxicity that is dependent on molecular weight, charge density, and polymer concentration. Lower molecular weight polymers and optimized charge ratios (N/P ratio in polyplexes) generally show reduced cytotoxicity. Thorough biological evaluation including cell viability assays is mandatory before any in vitro or in vivo application. Regulatory requirements for medical or therapeutic use must also be satisfied.

References

1. Teodorescu, M.; Matyjaszewski, K. Atom Transfer Radical Polymerization of (Meth)acrylates Containing Pendant Amine Groups. Macromolecules 1999.
2. Moad, G.; Rizzardo, E.; Thang, S. H. Living Radical Polymerization by the RAFT Process. Australian Journal of Chemistry, 2005.
3. van de Wetering, P. et al. 2-(Dimethylamino)ethyl Methacrylate Based (Co)polymers as Gene Transfer Agents. Journal of Controlled Release, 1998.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.