2,2'-Biphenol-based Ultrathin Microporous Nanofilms for Highly Efficient Molecular Sieving Separation

Area of Science:

• Polymer Science
• Materials Chemistry
• Separation Technology

Background:

• Organic solvent nanofiltration (OSN) requires advanced membranes with high permeance and selectivity.
• Current OSN membranes often lack the robustness and processability for widespread industrial adoption.

Purpose of the Study:

• To develop novel, hyper-crosslinked polymer nanofilms for enhanced OSN applications.
• To utilize 2,2'-biphenol (BIPOL) derivatives for fabricating robust and selective membranes.

Main Methods:

• Fabrication of ultra-thin (≈5 nm), defect-free nanofilms using interfacial polymerization (IP) with BIPOL derivatives.
• Characterization of membrane microporosity, molecular weight cut-off (MWCO), and permeance.
• Testing separation performance for small dye mixtures based on charge and size.

Main Results:

• Achieved ultra-thin, defect-free polyesteramide/polyester nanofilms due to BIPOL monomer properties retarding IP rate.
• Hyper-crosslinked network and monomer rigidity led to enhanced microporosity.
• Amino-BIPOL/PAN membrane demonstrated exceptional permselectivity with MWCO as low as 233 Da and MeOH permeance of ≈13 LMH/bar.
• Precise separation of small dye mixtures with similar molecular weights was achieved.

Conclusions:

• BIPOL derivatives are effective in creating hyper-crosslinked, microporous membranes for OSN.
• The developed membranes exhibit superior performance for separating small molecules in organic solvents.
• This work facilitates the industrial uptake of OSN technology through advanced membrane design.