Marine mussel inspired polydopamine (PDA) has received increased attention due to its good thermal and chemical stability as well as strong adhesion on most materials. In this work, high-performance nanofiltration membranes based on interpenetrating polymer networks (IPN) incorporating PDA and polybenzimidazole (PBI) were developed for organic solvent nanofiltration (OSN). Generally, in order to obtain solvent stability, polymers need to be covalently cross-linked under harsh conditions, which inevitably leads to losses in permeability and mechanical flexibility. Surprisingly, by in situ polymerization of dopamine within a PBI support, excellent solvent resistance and permeance of polar aprotic solvents were obtained without covalent cross-linking of the PBI backbone due to the formation of an IPN. The molecular weight cutoff and permeance of the membranes can be fine-tuned by changing the polymerization time. Robust membrane performance was achieved in conventional and emerging green polar aprotic solvents (PAS) in a wide temperature range covering a10 °C to +100 °C. It was successfully demonstrated that the in situ polymerization of PDA - creating an IPN - can provide a simple and green alternative to covalent cross-linking of membranes. To elucidate the nature of the solvent stability, a detailed analysis was performed that revealed that physical entanglement along with strong secondary interaction synergistically enable solvent resistance with as low as 1-3% PDA content.
Bibliographical noteFunding Information:
The authors would like to express their gratitude to Dr. Christopher Blanford and Mr. Fan Fei (Manchester Institute of Biotechnology) for the dielectric constant measurements. Training and consultancy provided by Dr. Christos Didaskalou (The University of Manchester) is greatly acknowledged by Dan Zhao. This work was supported by the Biotechnology and Biological Sciences Research Council [BB/L013770/1]. This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry, and Energy (MOTIE) of the Republic of Korea (nos. 201820101066550 and 20172010106170).
© 2019 American Chemical Society.
- in situ polymerization
- polar aprotic solvents
- surface modification
- temperature effect
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy