2-Hydroxyethyl Methacrylate (HEMA, CAS No. 868-77-9) is a hydroxy-functional methacrylate monomer containing both a polymerizable methacrylate group and a terminal hydroxyl group. Its molecular formula is C₆H₁₀O₃ and molecular weight is 130.14 g/mol.
The methacrylate double bond enables HEMA to participate in free-radical polymerization, while the hydroxyl group provides additional hydrophilicity and opportunities for hydrogen bonding, esterification, crosslinking, and surface modification.
HEMA is an important building block for hydrophilic polymers, hydrogels, biomaterials, dental materials, contact-lens materials, coatings, adhesives, and functional polymer systems.
HEMA contains a polymerizable carbon-carbon double bond:
CH₂=C(CH₃)COOCH₂CH₂OH
Under suitable free-radical initiation conditions, HEMA undergoes addition polymerization to form poly(2-hydroxyethyl methacrylate) (PHEMA):
n CH₂=C(CH₃)COOCH₂CH₂OH → –CH₂–C(CH₃)(COOCH₂CH₂OH)–ₙ
The resulting PHEMA contains hydrophilic hydroxyl groups and can absorb water, making it useful for hydrogel and biomaterial research.
HEMA can also be copolymerized with other methacrylate or acrylic monomers to tune:
PHEMA and HEMA-based copolymers are widely investigated as hydrophilic polymer and hydrogel materials.
HEMA is an important monomer in dental materials research, particularly in resin-based restorative and adhesive systems.
Applications include:
HEMA can contribute hydrophilic characteristics and improve interaction between resin systems and moist dentin surfaces. HEMA and HEMA-based polymers have also been investigated in dental composite materials and dental-pulp-related research.
Research focus: dental resin formulation, polymerization behavior, dentin bonding, water uptake, interface stability, and dental biomaterials.
HEMA is historically important in the development of hydrophilic contact-lens materials.
Polymerization of HEMA can produce hydrophilic PHEMA-based materials capable of absorbing and retaining water.
Applications include:
HEMA is widely used as a monomer for preparing hydrophilic polymers and hydrogel materials.
Applications include:
TCI specifically classifies HEMA under Biomaterials / Biocompatible Materials Research Reagents and Monomers and Macromonomers.
HEMA-based hydrogels can be designed to absorb water and provide controlled polymer networks.
Applications include:
HEMA-based hydrogel systems have been investigated for drug-release and drug-delivery applications.
HEMA can be incorporated into acrylic and methacrylate polymer systems to introduce hydroxyl functionality.
Applications include:
The hydroxyl group can provide additional sites for interactions and crosslinking with other components.
HEMA is used as a functional monomer in adhesive polymer systems.
Applications include:
The combination of a polymerizable methacrylate group and hydroxyl functionality makes HEMA useful for modifying adhesion and polymer–substrate interactions.
HEMA can participate in polymerization and crosslinking reactions used to develop photosensitive polymer systems.
Applications include:
HEMA can be incorporated into polymer systems designed to modify fiber surfaces.
Applications include:
Commercial application references also identify HEMA for fiber-treatment and acrylic resin modification.
HEMA is a reactive methacrylate monomer and is commonly supplied with a polymerization inhibitor such as MEHQ to improve storage stability. Commercial specifications from Sigma-Aldrich include grades containing ≤50 ppm or ≤250 ppm MEHQ.
HEMA can cause skin sensitization, so appropriate measures should be taken to minimize skin exposure. PubChem notes the sensitizing potential associated with methacrylates.
2-Hydroxyethyl Methacrylate (CAS No. 868-77-9) can be positioned across several specific industries and research fields:
| Research Area | Specific Industry / Application |
|---|---|
| Dental Materials | Dental adhesives, dentin bonding, dental composites, resin-based restorative materials |
| Contact Lens Materials | Soft contact lenses, hydrogel lenses, ophthalmic biomaterials |
| Biomedical Materials | Hydrogels, biomaterials, biointerfaces, tissue-engineering materials |
| Drug Delivery | Controlled-release hydrogels, drug-delivery polymer systems |
| Medical Devices | Hydrophilic polymer coatings and functional polymer materials |
| Coatings | Acrylic coatings, UV-curable coatings, functional surface coatings |
| Adhesives | Acrylic adhesives, pressure-sensitive adhesives, dental adhesives |
| Polymer Industry | Acrylic/methacrylate copolymers and functional polymer synthesis |
| Photosensitive Materials | Photopolymerizable resins and photosensitive coatings |
| Fiber & Textile | Fiber treatment and polymer-based surface modification |
| Surface Engineering | Hydrophilic surface modification and polymer interface engineering |
TCI's current application classification specifically includes Dental Materials Research Reagents, Biomaterials/ Biocompatible Materials, Methacrylate Monomers, Drug Delivery Systems, and Double Network Gel synthesis for HEMA.
A: 2-Hydroxyethyl Methacrylate (HEMA) is a hydroxy-functional methacrylate monomer with CAS No. 868-77-9, molecular formula C₆H₁₀O₃, and molecular weight 130.14 g/mol.
A: HEMA is used to prepare hydrophilic polymers, hydrogels, dental materials, contact-lens materials, biomedical materials, coatings, adhesives, and functional acrylic polymers.
A: Yes. HEMA is widely used in dental materials research, particularly in dental adhesive and resin systems. TCI explicitly lists HEMA under Dental Materials Research Reagents.
A: Its methacrylate group enables polymerization, while its hydroxyl group contributes hydrophilicity and interactions with substrates, making HEMA useful in dental adhesive formulations and dentin-bonding research.
A: Yes. HEMA is an important monomer for preparing hydrophilic PHEMA-based hydrogel materials, historically associated with soft contact-lens materials.
A: Polymerization of HEMA produces poly(2-hydroxyethyl methacrylate), or PHEMA, a hydrophilic polymer widely investigated in hydrogel and biomaterial research.
A: Yes. HEMA is used as a monomer for developing hydrogels, biomaterials, drug-delivery systems, and other functional polymeric materials.
A: Yes. Commercial HEMA is commonly supplied in stabilized form, such as MEHQ-stabilized HEMA, to reduce unwanted polymerization during storage.
