A "Green" Stirring Plasma Functionalization Strategy for Controllable Oxygen-Containing Functional Groups on...

Area of Science:

• Materials Science
• Surface Chemistry
• Green Chemistry

Background:

• Polyhedral oligomeric silsesquioxane (POSS) materials are effective fillers in composite membranes for separations.
• Surface functionalization is crucial for POSS applications but challenging with traditional wet-chemistry methods due to hazardous by-products.

Purpose of the Study:

• To present a "green" plasma strategy for functionalizing octa-methyl POSS sub-micron particles.
• To achieve designable oxygen-containing functional groups on POSS surfaces.
• To offer an environmentally friendly alternative to wet-chemistry approaches.

Main Methods:

• Utilized a low-pressure oxygen plasma with combined continuous wave (CW) and pulsed (CW+P) modes.
• Employed CW mode for surface etching and activation of POSS.
• Used pulsed plasma to graft oxygen species onto methyl groups, forming hydroxyl and carboxyl groups.

Main Results:

• Successfully functionalized octa-methyl POSS sub-micron particles with oxygen-containing groups.
• Achieved precise control, yielding approximately one hydroxyl or carboxyl group per POSS cage corner.
• Demonstrated functionalization without damaging the POSS core structure.

Conclusions:

• The presented plasma process is a controllable method for surface functionalization of sub-micron particles.
• This approach offers a more environmentally friendly pathway for preparing functionalized POSS fillers.
• The findings support the use of plasma technology for designing advanced materials for separation applications.