Metal Oxide-Polymer Hybrid Material Synthesis via Metal Nitrate Infiltration and Decomposition

Synthesis of metal oxides within polymers by vapor phase infiltration (VPI), also known as sequential infiltration synthesis, is a powerful approach to create polymer-inorganic hybrid materials with enhanced chemical resistance and thermal stability, modified and augmented interfacial properties, and added functionality. Liquid phase infiltration, the incorporation of metal salts from solution into polymers, is an attractive alternative to VPI in terms of material diversity, precursor cost, and process scalability. However, these salts have not previously been converted to metal oxides without polymer destruction. Here, we show that liquid phase infiltrated metal nitrates can be converted to metal oxides within the polymer in situ through low-temperature thermal or photolytic decomposition, enabling nondestructive synthesis of polymer-metal oxide hybrids. Using poly(vinyl pyridine)-based polymers, we demonstrate two exemplary use cases: (1) surface functionalization with a hybrid iron oxide-polymer brush layer that exhibits electrokinetic properties (e.g., streaming potentials, effective surface charge, surface conductivity) nearly equivalent to the standalone iron oxide, and (2) prescriptive reduction of self-assembled pore sizes at sub-10 nm dimensions via incorporation of copper oxide.