Branched polyethylenimine (bPEI), nominal MW ~1,200, is a low-molecular-weight branched polyamine containing primary, secondary, and tertiary amine groups. These protonatable amines give PEI pH-dependent cationic character and provide multiple sites for ionic interaction, complexation, surface adsorption, and chemical modification.
Synonyms: PEI; bPEI; branched PEI; branched poly(ethylene imine). CAS: 9002-98-6.
The branched architecture contains primary, secondary, and tertiary amines in an approximately 1:2:1 distribution. This grade has a nominal molecular-weight designation of ~1,200, an assay of ≥99%, and a viscosity specification of 3,500–7,500 cP at 25°C.
The degree of protonation of PEI depends on pH and solution conditions. This variable cationic character is important in applications involving negatively charged surfaces, ionic species, polymers, particles, and other materials capable of interacting with protonated amine groups.
Key Properties
- Branched polyethylenimine (bPEI)
- Nominal molecular weight: ~1,200
- CAS number: 9002-98-6
- Assay: ≥99%
- Appearance: colorless or light-yellow liquid
- Viscosity at 25°C: 3,500–7,500 cP
- pH of 5% aqueous solution: 10–12
- Contains primary, secondary, and tertiary amines in an approximately 1:2:1 distribution
- Storage: room temperature
Applications
Cationic Polymer & Complexation Research
Branched PEI is used in studies involving protonatable polyamines, electrostatic interactions, ionic complexation, and the behavior of cationic polymers. Interaction strength depends on variables including pH, ionic strength, concentration, and the chemistry of the interacting species.
Surface Modification & Functionalization
PEI may be used in surface-treatment and functionalization workflows where an amine-rich polymer is adsorbed onto compatible substrates or used to introduce accessible amine functionality for subsequent chemical modification.
Coatings, Adhesives & Formulation Research
Polyethylenimine materials are used in coating and adhesion-related formulations because protonated amines can interact with negatively charged or polar surfaces. Performance is formulation-dependent and varies with substrate chemistry, pH, concentration, and other formulation components.
Polymer Modification & Derivative Synthesis
The primary and secondary amines of branched PEI provide reactive sites for derivatization and conjugation chemistry. Low-molecular-weight PEI is therefore used as a polyamine building block in research involving modified cationic polymers and PEI-based conjugates.
Solution Behavior & Reactivity Considerations
- The pH of a 5% aqueous solution is specified at 10–12
- Cationic character depends on the protonation state of the amine groups
- Protonation and electrostatic interactions vary with pH, ionic strength, and formulation composition
- Primary and secondary amines provide sites for appropriate derivatization and conjugation reactions
Because branched PEI contains chemically distinct amine environments, its behavior should not be represented by a single fixed charge state. Surface adsorption, complexation, and chemical reactivity depend on the conditions of the specific system.
Application Tips
- Control pH and ionic strength when evaluating electrostatic interactions or complexation behavior
- Keep polymer concentration, mixing order, and contact time consistent when comparing formulations
- For chemical modification, account for the presence of primary, secondary, and tertiary amine environments when selecting reaction conditions
- Evaluate compatibility with the intended substrate, polymer, particle, or formulation under application-specific conditions
Handling & Storage
- Store at room temperature in a cool, well-ventilated location
- Ensure good laboratory ventilation during handling
- Wear protective gloves and safety glasses
- Wear suitable protective clothing and avoid skin contact
Why Choose Polysciences?
Trusted by 6,000+ Researchers Worldwide
Cited in Thousands of Peer-Reviewed Studies
U.S. Manufacturing & Global Distribution
Reliable Delivery to 40+ Countries
FAQ
Click a question to expand.
1. What is branched polyethylenimine MW 1,200 used for?
Branched polyethylenimine MW ~1,200 is used in cationic polymer research, ionic complexation studies, surface modification, coating and adhesion-related formulation work, and chemical modification of amine-functional polymers.
2. What does MW 1,200 mean for bPEI 1200?
The ~1,200 value is the nominal molecular-weight designation for this branched PEI grade. The current product specification does not identify a separate number-average or weight-average molecular-weight measurement method for this value.
3. What is the viscosity of branched PEI MW 1,200?
The viscosity specification is 3,500–7,500 cP at 25°C. This is a dynamic viscosity specification and should not be described as intrinsic viscosity.
4. How does branched PEI differ from linear PEI?
Branched PEI contains primary, secondary, and tertiary amine groups throughout a branched architecture. Linear PEI has an unbranched backbone dominated by secondary amine functionality. Architecture and molecular weight influence charge behavior, solution properties, reactivity, and application performance.
5. Is bPEI 1200 used in nucleic-acid delivery research?
Low-molecular-weight branched PEI has been studied in nucleic-acid delivery research, particularly as a starting material for chemically modified PEI derivatives and conjugates. Performance depends strongly on polymer architecture, molecular weight, chemical modification, formulation conditions, N/P ratio, and biological system, so bPEI 1200 should not be assumed to perform interchangeably with higher-molecular-weight PEI transfection reagents.
Safety & Documentation
Branched polyethylenimine MW 1,200 is classified as harmful in contact with skin and as a skin irritant. Use appropriate laboratory ventilation, protective gloves, safety glasses, and suitable protective clothing. Store at room temperature in a cool, well-ventilated location. Refer to the product Safety Data Sheet (SDS) for complete handling and safety guidance.
