Precipitation of a water soluble ABC triblock methacrylic polyampholyte: Effects of time, pH, polymer concentration, salt type and concentration, andpresence of a protein
Cs. Patrickios et al., Precipitation of a water soluble ABC triblock methacrylic polyampholyte: Effects of time, pH, polymer concentration, salt type and concentration, andpresence of a protein, LANGMUIR, 15(5), 1999, pp. 1613-1620
The solution behavior of a low molecular weight ABC triblock methacrylic po
lyampholyte with the structure (dimethylaminoethyl methacrylate)(8)-(methyl
methacrylate)(12)-(methacrylic acid)(16) was investigated by turbidimetry.
The variation of the optical density at 420 nm of dilute polyampholyte sol
utions with time, pH, polymer concentration, salt type and concentration, a
nd presence of a protein was explored. Polyampholyte precipitation was fast
and occurred around the isoelectric pH. The size of the aggregates increas
ed with increasing salt concentration and was independent of polyampholyte
concentration. High salt concentrations suppressed polyampholyte precipitat
ion. The precipitation in the presence of various electrolytes at a concent
ration of 0.2 M was insensitive to the anion type for a series of potassium
halides and also to the divalent sulfate anion, but was greatly increased
by the divalent calcium cation and was completely suppressed by the anionic
surfactant sodium dodecyl sulfate. The polyampholyte formed insoluble comp
lexes with a basic protein, chicken egg lysozyme in the pH region between t
he isoelectric points of the two reactants. The results of this study will
be useful for designing the extraction of solutes, such as heavy metals and
proteins, via polyampholyte electrostatic complexation; moreover, they wil
l facilitate the development of efficient strategies for polyampholyte reco
very and recycling.