A series of new hydrolytically stable poly(carbobetaine)s with varying dist
ance between the ammonium and the carboxylate group was synthesized, exclud
ing the presence of residual salt in the polymers, together with cationic a
nd sulfobetaine analogues. The poly(carbobetaine)s show improved solubility
compared to analogous poly(sulfobetaine)s, and are more hygroscopic. Their
thermal stability depends strongly on the length of the spacer group separ
ating the ammonium and the carboxylate group. The poly(carbobetaine)s are t
ypically amorphous, but for long spacer groups, they exhibit a superstructu
re. They are capable of forming homogeneous blends with a number of inorgan
ic salts, following the selectivity of the Hofmeister series, thus giving a
ccess to new organic-inorganic hybrid materials.