Emerging sensing platforms often use receptors for target-specific recognition for sensitive and selective detections of trace contaminants. A promising method involves monitoring the changes in interfacial tension (IFT) at liquid-liquid interfaces that are induced by selective recognition of novel polymeric surfactants and the targeted analytes. This study analyzes the bulk, interfacial, and electrokinetic properties of ionic amphiphilic block copolymers (BCPs)—poly(styrene)-block-poly(acrylic acid) (PS-b-PAA) and poly(styrene)-block-poly(4-vinyl pyridine) (PS-b-P4VP) under different controlled environments. We test the hypothesis that the interfacial behaviors of these receptors depend on the relative strength of the hydrophilic and hydrophobic blocks by modifying them through post-polymerization functionalization with different amino acids. Specifically, we characterize the different functionalized polymers using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic light scattering (DLS), zeta potentials, and pendant drop tensiometry. We observed that a more uniform molecular weight distribution of the BCPs and post-polymerization functionalization with electrically charged side-chain amino acids improved the interfacial sensitivity, where electrical complexation and hydrophobic forces played a crucial role in interfacial modulation. We anticipate that this study will provide insights for interfacial interactions of biomimetic polymers, which will leverage for rapid, portable detection of biohazardous contaminants.
