Thermo Scientific™ Polyethyleneimine (PEI), M.W. 70,000 (branched), supplied as a 30% (w/v) aqueous solution, is a high–molecular-weight cationic polymer widely used for protein purification, nanoparticle stabilization, chelation, flocculation, and industrial processing. The branched PEI structure contains a rich distribution of primary, secondary, and tertiary amines, delivering exceptional cationic charge density and reactivity.

This grade is optimised for the precipitation of proteins, making it useful in biochemical workflows for clarification, concentration, and purification. Its strong binding affinity for anionic biomolecules, metal ions, aldehydes, and oxides makes it an essential reagent in biotechnology, water treatment, papermaking, dye/pigment processing, and specialty chemical manufacturing.

Supplied as a colourless to pale yellow, odourless liquid, this PEI solution is easy to use, miscible with water, and stable at ambient temperature.

Key Features & Benefits

High-Molecular-Weight PEI (M.W. 70,000)

• Strong flocculation, precipitation, and binding activity
• Forms robust polyelectrolyte complexes with proteins, nucleic acids, and anionic polymers
• Excellent for industrial and biochemical separations

30% (w/v) Aqueous Solution

• Ready-to-use format
• Lower viscosity compared to solid PEI grades
• Easily diluted and mixed with aqueous buffers
• Ideal for biochemical and industrial workflows

Highly Functional Branched Polyamine

• Effective protein precipitant
• Strong chelating agent for metals
• Efficient scavenger for aldehydes and reactive oxides
• Supports nanoparticle coating and surface modification

Industrial Versatility

Widely used in:

• Detergents and cleaner formulations
• Paper and pulp processing
• Dye and pigment manufacturing
• Printing inks and coating systems
• Water treatment and flocculation processes

Chemical & Regulatory Information

Applications

1. Biotechnology & Protein Chemistry

• Protein precipitation for purification and fractionation
• Removal of nucleic acids from lysates
• Clarification of fermentation broths
• Preparation of protein-free supernatants

2. Chemical & Polymer Synthesis

• Crosslinking agent and adhesion promoter
• Intermediate in functional polymer development
• Stabilisation of nanoparticles and colloidal suspensions

3. Industrial Manufacturing

• Additive in detergents
• Paper industry wet-strength and retention aid
• Dye and pigment processing
• Printing inks and coating formulations

4. Water & Environmental Treatment

• Strong cationic flocculant
• Efficient metal chelator
• Scavenger for aldehydes, oxides, and anionic contaminants

Ordering Information

Thermo Scientific™ Polyethyleneimine (PEI), M.W. 70,000, 30% (w/v) in aqueous solution, is a high–molecular-weight branched polyamine ideal for protein precipitation, metal chelation, nanoparticle functionalisation, and industrial processing. Its high charge density, strong binding capability, and ready-to-use aqueous format make it a powerful reagent for biotechnology, chemical synthesis, water treatment, and industrial formulations.