Using reversibility of the dynamic covalent bond to create porosity in highly ordered polymer thin films under mild conditions and nano-pore functionalization in the gas phase

Phase-separating polystyrene (PS) and polyethylene glycol (PEG) polymers are connected through a hydrazone-based reversible covalent bond to afford a PS–CHN–PEG diblock copolymer. This novel dynamic covalent copolymer assembles into a nano-structured cylindrical morphology in thin films. Reversal of the hydrazone linkage and removal of PEG–hydrazide under mild conditions afford a nano-porous membrane featuring a chemically reactive functionality in the nano-pores. Availability of these reactive groups for further thin film functionalization is demonstrated by re-establishing the imine bond with a small molecule amine. This modification strategy does not require any coupling reagent, solvent, or high temperature. Therefore, a gas-phase technique is sufficient for film functionalization purposes.