Thiol-Ene Interfacial Photo-Cross-Linking for Ultrathin Rubbery Polymer and Nanoparticle Films as Membrane Selective...

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Chemistry

Background:

• Thin-film composite (TFC) membranes are crucial for separations, but their chemistry is largely limited to polyamides.
• Interfacial polymerization (IPz) is a key fabrication method for TFC membranes.
• Developing new chemistries for IPz is essential for advancing membrane technology.

Purpose of the Study:

• To introduce a novel thiol-ene interfacial photo-cross-linking strategy as an expansion of IPz.
• To demonstrate the fabrication of ultrathin films for membrane selective layers using this new method.
• To explore the versatility and scalability of this photo-cross-linking approach.

Main Methods:

• Utilized vinyl-rich polymers (PDMS, PB) and vinyl-functionalized silica nanoparticles (SiNPs).
• Cross-linked materials with dithiols at a water/oil interface under UV irradiation in ambient air.
• Analyzed film properties using infrared spectroscopy and electron microscopy.

Main Results:

• Successfully formed nonporous (PDMS, PB) and porous (SiNPs) ultrathin films.
• PB-derived films exhibited low thicknesses (60-200 nm) with high phenol/NaCl selectivities (up to 2000).
• Demonstrated efficient thiol-ene addition and continuous film coverage, highlighting the method's robustness.

Conclusions:

• The thiol-ene interfacial photo-cross-linking strategy is a versatile, oxygen-tolerant, and scalable platform for fabricating ultrathin selective layers.
• This method expands the chemical possibilities beyond traditional polyamide IPz.
• Provides a foundation for creating chemically modifiable nonporous and porous nanofilms for future separation applications.