Amphiphilic zwitterionic poly(dimethylsiloxane) (PDMS)-contained poly(ether amine) (Z-SiPEA) as the responsive polymeric dispersant

We demonstrated here a novel concept of the responsive dispersant based on the amphiphilic zwitterionic poly(ether amine) (Z-SiPEAs), which can control the dispersion of dyes and pigments in water. Z-SiPEAs are composed of short poly (dimethylsiloxane) (PDMS) chain in the backbone and Jeffamine L100 as graft chain. The amino groups in the backbone and carboxyl groups grafted to the backbone make the obtained Z-SiPEAs zwitterionic. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) results revealed that the obtained Z-SiPEAs can self-assemble into nanoparticles in water, which possessed sharp response to temperature, pH, and ionic strength with the tunable clouding point (CP). In the presence of Z-SiPEAs, not only hydrophobic dyes such as Nile Red can be dispersed in water, but the hydrophilic dye Rose Bengal (RB) can be dispersed in unpolar solvents. Further more, Z-SiPEAs can enhance the dispersion of inorganic pigments Titanium White, Iron Red and Chrome Yellow very efficiently in most solvents. It should be noted that the dispersion of organic dyes and inorganic pigments in water can be controlled by temperature in the presence of Z-SiPEAs. 1H NMR and FT-IR revealed the strong coordination between carboxyl groups in Z-SiPEAs and metal atoms of inorganic pigments. These characteristics will give Z-SiPEAs potential as the novel responsive polymeric dispersant.