Patterned Hydrophilization of Nanoporous 1,2-PB by Thiol-ene Photochemistry

We present an efficient method for functionalizing the large polymer–air interface of a gyroid nanoporous polymer. The hydrophilicity of nanoporous cross‐linked 1,2‐polybutadiene is tuned by thiol‐ene photo‐grafting of mercaptosuccinic acid or sodium 2‐mercaptoethanesulfonate. The reaction is monitored by FT‐IR, UV–Vis, contact angle, and gravimetry. Overall quantum yields are calculated for the two thiol‐ene “click” reactions in nano‐confinement, neatly revealing their chain‐like nature. Top–down photolithographic patterning is demonstrated, realizing hydrophilic nanoporous “corridors” exclusively hosting water. The presented approach can be relevant for many applications where, e.g., high control and contrast in hydrophilicity, chemical functionality or refractive index are needed. The gyroid nanoporous 1,2‐polybutadiene polymer‐air interface is hydrophilized by use of thiol‐ene photochemistry. The reaction of two chosen thiols containing hydrophilic groups with the double bonds of 1,2‐PB at the vast nanoporous surface area is fast, specific, and quantitative. Quantum yields for the photo‐grafting reactions are calculated and confirm the chain‐like nature of the reactions. Hydrophilic volume patterning is demonstrated.