Hyperbranched polyethylenimine bearing cyclodextrin moieties showing temperature and pH controlled dye release

The release of anthraquinone dyes from β-cyclodextrin modified, hyperbranched polyethylenimine (PEI-CD) was investigated. 5,8-Dichloro-1,4-dihydroxyanthraquinone (AQ-OH) was enclosed simply by ionic attraction between the phenolate groups of AQ-OH and the protonated amino groups of polyethylenimine (PEI). Additionally, the adamantyl moieties of 1,4-bis-N-adamantylaminoanthraquinone (AQ-Ada) were encapsulated by the cavity of CD modified PEI. Due to these different types of interaction, the dyes can be controllably released from the CD-cavity (AQ-Ada) by temperature variation or from salt encapsulation by pH variation (AQ-OH), as monitored by UV–vis spectroscopy.