In Situ Hydrolysis of Block Copolymers at the Water‐Oil Interface

Abstract

In situ manipulation of the chemical composition of block copolymers at the fluid interfaces affords a route by which the interfacial tension, the packing of the copolymers, and the penetration of the blocks into the two liquids can be controlled. Here, a series of linear block copolymers of poly(solketal methacrylate‐b‐styrene) (PSM‐b‐PS) are used, converting hydrophobic PSM block into a hydrophilic glycerol monomethacrylate (GM) block, that results in a marked decrease in the liquid‐liquid interfacial tension. The kinetics of the first‐order hydrolysis reaction was analyzed by monitoring the time‐dependent interfacial tension as a function of pH, polymer concentration, molecular weight, and composition. Fluorescence recovery after photobleaching (FRAP) was used to measure the in‐plane dynamics of the copolymers before and after hydrolysis. This work provides insights into a quantitative pathway by which in situ interfacial reactions may be performed and monitored in real time, completely changing the interfacial activity of the molecule.

Using Grazing-Incidence Small-Angle Neutron Scattering to Study the Orientation of Block Copolymer Morphologies in Thin Films

“…We recently reported the synthesis of poly­(solketal methacrylate)- block -polystyrene (PSM- b -PS) and its hydrolysis into poly­(glycerol monomethacrylate)- block -polystyrene (PGM- b -PS). , The hydrolysis from hydrophobic–hydrophobic block copolymers (BCPs) into hydrophilic–hydrophobic BCPs changed the BCPs from being disordered to strongly microphase separated. The segmental interaction parameter (χ) significantly increased 13 times after hydrolysis, from 0.035 to 0.438 at 25 °C using 118 Å 3 as a reference volume .…”