Alternating Amphiphilic Copolymers in Water
Amphiphilic polymers exhibit diverse self-assembly behaviors in aqueous solutions. Experimental studies often focus on statistical or block copolymer architectures due to their ease of synthesis and similarity to surfactants. Alternating copolymers, linking these architectures, are synthesized using polycondensation reactions with hydrophobic dicarboxylic acids (C4–C20) and hydrophilic poly(ethylene glycol) (PEG) units (EG3–EG1000).
A new esterification process enabled the synthesis of copolymers with long EG units. These copolymers show lower critical solution temperature (LCST) behavior in water, adjustable from 3 to 83 °C by varying the lengths of the Cn and EGm units. The transition temperature depends linearly on the hydrophobic unit length Cm and logarithmically on the hydrophilic length EGn. In the one-phase region, PEG copolymer coils are more compact than PEG homopolymers due to hydrophobic interactions. Shorter PEG units form micellar structures with hydrophobic cores and PEG-rich coronas.
Further decreasing PEG unit length leads to highly swollen gels and highly ordered liquid crystalline cubic phases. We study how alternating amphiphilic copolymers can be systematically varied to adjust thermal solution properties and self-assembly behaviors, ranging from single chains to micelles, gels, and lyotropic liquid crystals.
Contact:
- Jülich Centre for Neutron Science (JCNS)
- Neutron Scattering and Soft Matter (JCNS-1)
Room 290