Solvent quality dependent interactions between adsorbed block copolymers measured by AFM

Ionic Strength-Dependent Interactions and Dimensions of Adsorbed Zwitterionic Copolymers

“…However, dipole moment alone does not sufficiently explain zwitterionic polymer solution behavior. For example, PMPC does not exhibit ionic strength-dependent dimensions in solution or on surfaces, ,− despite having a similar dipole moment to PMAPS . One explanation is the importance of specific solvation effects, as PMPC analogs with reversed dipole orientations (phosphate–amine to amine–phosphate) displayed ionic strength-dependent dimensions typical of other zwitterionic polymers …”

“…Measurements of silica surfaces with grafted zwitterionic layers as a function of ionic strength have also been used to infer thicknesses (normal compression) and frictional properties (lateral motion). , However, while such measurements provide information on zwitterionic layer thicknesses, they do not reveal information about ionic strength-dependent interactions. Finally, measurements of interactions between zwitterionic layers on opposing surfaces have primarily focused on contact adhesion and lubrication. − However, these studies investigated how ionic strength-dependent electrostatic and dipolar contributions determine net zwitterionic layer intra- and intermolecular interactions relevant to phase behavior of bulk polymers and polymer-coated colloids. , In particular, prior measurements have not interrogated weak interpenetration and compression at the polymer periphery (i.e., vanishing density profile) that determines net polymer mediated kT -scale interactions …”

kT-Scale Interactions and Stability of Colloids with Adsorbed Zwitterionic and Ethylene Oxide Copolymers

“…First-principles design of copolymer compositions and architectures is not trivial based on a complex balance of segment, solvent, and surface interactions. However, copolymers capable of forming thick, dense layers via physisorption have been identified. , A notable example is PEO–PPO–PEO triblock copolymers, which are well established for stabilizing hydrophobic colloids in aqueous media. ,, While a number of studies have investigated the phase behavior and emulsion stabilizing ability of zwitterionic copolymers, − less have explored their use as colloidal stabilizers. , Many studies have explored synthesis of novel polymers, but none have systematically studied connections between layer properties, interactions, or effects on colloidal aggregation and deposition.…”

“…Although interactions of zwitterionic and EO polymers determine all of their behaviors and properties, a limited number of studies have directly measured or modeled such interactions. Several studies have measured polymer layer interactions, − typically at high applied normal forces that produce significant compression. High normal forces and layer deformation are important to adhesion, friction, and lubrication between adsorbed layers but are less relevant to colloidal stability.…”