Schizophrenic micelles of poly(3-(methacryloylamino)propyltrimethylammonium chloride-b-2-(dimethylamino)ethyl methacrylate) in aqueous solutions

• PMAPTAC-b-PDMAEMA aqueous solution produces two distinct types of micelle structures in response to external stimuli.
• DMAEMA-core/PMAPTAC-corona micelles at pH > 8, T > LCST.
• MAPTAC-core/PDMAEMA-corona micelles are formed by adding SDS.
• The two types of micelles can be reversibly converted to each other.

Micelles of poly(3-(methacryloylamino)propyltrimethylammonium chloride-b-2-(N,N-dimethylamino)ethyl methacrylate) (PMAPTAC-b-PDMAEMA), a double hydrophilic block copolymer, have been prepared in aqueous solution by insolubilizing one of the blocks with external stimuli. PMAPTAC-core micelles were formed by addition of sodium dodecyl sulfate (SDS) to insolubilize the PMAPTAC block. On the other hand, PDMAEMA-core micelles were formed by increasing temperature at higher pH. It was revealed that these two types of the micelles can be reversibly converted to each other. The PMAPTAC/SDS-core micelles were collapsed to the unimers by removing SDS with anion exchange resin, followed by increase in temperature to form the PDMAEMA-core micelles. The PDMAEMA-core micelles were destructed to the unimers by decreasing temperature, followed by addition of SDS to form the PMAPTAC/SDS-core micelle. The micelle properties were extensively investigated by dynamic light scattering, scanning electron microscopy, ζ-potential, and turbidity measurements.

Schizophrenic behavior of PMAPTAC-b-PDMAEMA diblock copolymer in an aqueous solution.Figure optionsDownload as PowerPoint slide