In this paper, it is shown that tertiary amine methacrylate-based diblock c
opolymers can form both micelles and reverse micelles in aqueous solution a
t room temperature. This remarkable behavior is due to subtle variations in
the hydrophilic-hydrophobic balance of the two block sequences, which are
based on 2-(diethylamino)ethyl methacrylate (DEA) and 2-(N-morpholino)ethyl
methacrylate (MEMA). H-1 NMR spectroscopy studies indicate that these DEA-
MEMA copolymers dissolve molecularly in water at pH 6-7 at 20 degreesC. DEA
-core micelles are formed at higher pH, and MEMA-core micelles are formed a
t pH 6.5 in the presence of 1.0 M Na2SO4. Both types of micelles were chara
cterized in terms of their intensity-average diameters and mean aggregation
numbers using dynamic and static light scattering, respectively. In additi
on, one of the copolymers (60 mol % MEMA, M-w = 30 000, M-w/M-n = 1.05) was
selected for a detailed small-angle neutron scattering (SANS) study. SANS
data for the micelles were analyzed in terms of a weakly interacting polydi
sperse sphere model and were in reasonable agreement with the light scatter
ing data. The DEA-core micelles are larger than the MEMA-core micelles, but
both light scattering and SANS data indicated that the DEA-core micelles h
ad a lower mean aggregation number than the MEMA-core micelles. This sugges
ts that the MEMA-core micelles are relatively dense and compact compared to
the more loosely packed DEA-core micelles.