Effects of the Ionizable Monomer Fraction on the Swelling Behavior of Weak Polyelectrolyte Brushes

• DOI: 10.1021/acs.macromol.3c00947
• Publication Date: 2023-11-10T15:32:45Z
• Authors: Shahryar Ramezani...; Farshad Safi Samg...; Si Li; Jacinta C. Conrad; Amanda B. Marciel
• Keywords: Zeta potential; Mole fraction; Hysteresis

Through a combination of in situ ellipsometry and streaming zeta potential measurements, we investigated the swelling behavior weak polybasic brushes as function pH fraction ionizable monomers f. The monomer (2-(dimethylamino)ethyl acrylate, DMAEA) was precisely tuned by mixing neutral hydrophilic (2-hydroxyethyl HEA) from f = 1.00 to 0.00. All charge containing fractions show pH-responsive behavior. At acidic pH, are within strongly charged osmotic brush regime, ratio increases with increasing f, qualitatively agreeing scaling laws for polyelectrolyte (PEBs). Moreover, DMAEA is increased, transition (pH*) shifts more basic values, indicating that ionization becomes favorable In intermediate range, all charge-containing hysteretic behavior, where pH* values backward direction shift extent hysteresis Streaming measurements good agreement observed at minimum maximum ranges fractions. However, isoelectric point (pI) consistently larger than no appreciable present measurement cycles. We propose hydrophobic periphery mechanism source experiments hypothesize origin disparity between pI probing length scale differences two methods. These findings elucidate effects on state PEBs, which can lead tailored surfaces many applications.