Details

Autor(en) / Beteiligte

• Hildebrand, Viet
• Laschewsky, André
• Zehm, Daniel

Titel

On the hydrophilicity of polyzwitterion poly (N,N-dimethyl-N-(3-(methacrylamido)propyl)ammoniopropane sulfonate) in water, deuterated water, and aqueous salt solutions

Ist Teil von

• Journal of biomaterials science. Polymer ed., 2014-01, Vol.25 (14-15), p.1602-1618

Ort / Verlag

England: Taylor & Francis

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Taylor & Francis

Beschreibungen/Notizen

• A series of zwitterionic model polymers with defined molar masses up to 150,000 Da and defined end groups are prepared from sulfobetaine monomer N,N-dimethyl-N-(3-(methacrylamido)propyl)ammoniopropanesulfonate (SPP). Polymers are synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT) using a functional chain transfer agent labeled with a fluorescent probe. Their upper critical solution temperature-type coil-to-globule phase transition in water, deuterated water, and various salt solutions is studied by turbidimetry. Cloud points increase with polyzwitterion concentration and molar mass, being considerably higher in D 2 O than in H 2 O. Moreover, cloud points are strongly affected by the amount and nature of added salts. Typically, they increase with increasing salt concentration up to a maximum value, whereas further addition of salt lowers the cloud points again, mostly down to below freezing point. The different salting-in and salting-out effects of the studied anions can be correlated with the Hofmeister series. In physiological sodium chloride solution and in phosphate buffered saline (PBS), the cloud point is suppressed even for high molar mass samples. Accordingly, SPP-polymers behave strongly hydrophilic under most conditions encountered in biomedical applications. However, the direct transfer of results from model studies in D 2 O, using, e.g. 1 H NMR or neutron scattering techniques, to 'normal' systems in H 2 O is not obvious.