A series of sulfonic acrylate ternary random copolymer surfactants (APSA) were synthesized through radical solution copolymerization

using styrene (St)

butyl acrylate (BA) and 2-acrylamide-2-methyl- propanesulfonic acid (AMPS) as raw materials.The structure of APSA copolymers was demonstrated by Fourier transform infrared spectroscopy (FTIR)

nuclear magnetic resonance spectroscopy (1H-NMR

13C-NMR)

gel permeation chromatography (GPC) and elemental analysis.In addition

the micromorphology

size and aggregation behaviors of APSA micelles were investigated by dynamic light scattering (DLS)

transmission electron microscopy (TEM)

surface tension analysis

steady state rheological analysis and steady-state fluorescence.TEM results showed that APSA micelles displayed as core-shell spheres

and the thickness of hydrophilic layer on the surface of APSA micelles increased with increasing the content of anionic hydrophilic sulfonic groups.Steady rheology analysis indicated that the viscosity of APSA solutions increased with increasing the content of sulfonic groups at lower shear rates

the interactions among micelles increased

and the pseudoplastic behavior was also improved.However

the viscosity of APSA solutions was almost invariable at higher shear rates.DLS and surface tension results suggested that the surface tension of APSA1 solution decreased to 43.26 mN/m.The surface tension and critical micelle concentration (cmc) increased with increasing the content of hydrophilic groups.When the APSA concentration was lower than cmc

the light scattering intensity was very low and increased very slowly

but the light scattering intensity displayed abrupt linear increasing trend when the APSA concentration was greater than cmc.At the same time

the aggregation number of APSA micelles increased greatly.DLS analysis also showed that aggregation behavior among micelles was enhanced with increasing APSA concentration

as well as the number of molecules inside the micelles

resulting in the increase of micelle size and dispersion index.Furthermore

the micelle size and dispersion index also increased with increasing the content of hydrophilic groups.It was also found from the fluorescence spectra that I1/I3 values decreased from 1.8 to 1.2 and then leveled off with increasing APSA concentration

the absorption peak of pyrene (0

0) shifted from 334 nm to 334 nm

I338/I334increased from 0.7 to 1.45.The above-mentioned results certified that the hydrophobic groups tended to aggregate and form hydrophobic microdomains

and pyrene molecules transferred from the aqueous polar phase to micellar interphase.It became more difficult for molecules to aggregate to form micelles with increasing the content of hydrophilic groups

and the formation velocity of micelles was also decreased.