As
a new example of intrinsically water-triggered phenomena, we
report underwater dehydration of the statistical copolymers synthesized
from triethanolamine borate (TEAB) methacrylate and styrene (St) induced
by the hydrolysis of the pendant TEAB group. TEAB possesses high polarity
owing to its internal Lewis adduct structure, which is lost by hydrolysis
to triethanolamine (TEA) with a lower dipole moment. Therefore, the
hydration of the copolymers became unfavorable through the hydrolysis
of the pendant TEAB to TEA, despite polyol formation, and through
a hydrophobic interaction based on St moieties becoming alternatively
dominant. The dehydration behavior of the copolymers, along with the
hydrolysis of the pendant TEAB group, was systematically investigated.
The water solubility of the copolymers was found to be dependent on
the gradient of the hydrolysis equilibrium of TEAB on the side chains
and was the lowest for the TEA state. These findings offer a novel
concept toward designing water-responsive materials.