pH Dependence of Acrylate-Derivative Polyelectrolyte Properties

Abstract

There are many polymers formed of acrylate monomers in existence. Here we interrogate four commonly-used examples and study how their solution properties are pH dependent, or how their state of ionisation can affect their solution properties. Poly(acrylic acid) and poly(methacrylic acid) are both polyelectrolytes, with ionisable functional groups that make them stimuli responsive, changing their hydrodynamic volume. Poly(acrylamide) is a mass-produced material used in a variety of industrial applications, often with an anionic and cationic co-monomer, which dictates both its efficacy and impact on the environment. Poly(N-isopropyl acrylamide) is a thermally responsive material with applications in smart bioengineering. In solution, these materials can interact with each other due to competing hydrogen bonding interactions. However, this interpolymer complexation is dependent on both the ionisation, and the conformational state, of the polymers involved. This review focuses on the results from fluorescence tagging and turbidimetric techniques.

Advancing bone tissue engineering one layer at a time: a layer-by-layer assembly approach to 3D bone scaffold materials

“…Yang et al reported the thickness of 30 bilayers of PEI/PAA bilayers to be 4740, 890, 350 or 90 nm depending on the combinations of pH values of solutions (10/4, 8/6, 4/4 and 7/7, respectively for PEI/PAA) 108,109. Kim et al reported that the thickest PAA/PEI films with the highest elastic modulus were assembled when the pH of PAA was 4, and the pH of PEI was 10, after considering pH values of 6, 8 and 10 (Fig.…”

Influence of Tacticity on the Structure Formation of Poly(methacrylic acid) in Langmuir/Langmuir–Blodgett and Thin Films

“…[ 35 ] As can be seen in Figure 1, no isotherm is possible at a subphase pH of 7, meaning that the Langmuir film of it ‐PMAA is only stable up to a certain subphase pH. This is because at a subphase pH of 7, more than 33% carboxylic groups of it ‐PMAA can be ionized as calculated by the Henderson‐Hasselbalch equation [ 36 ] considering p K a value of it ‐PMAA ≈7.3. [ 37,38 ] The ionization enhances the hydrophilicity of the polymer chain and solubilizes the Langmuir film in the water subphase.…”