Supramolecular assembly of dendronized spiropyrans in aqueous solutions into nanospheres with photo- and thermo-responsive chiralities
S.R. Qi, Xueting Lu, Wen-Li Mei, Guanglei Gu, Wen Li, Afang Zhang
Abstract
s) being dependent on the overall hydrophilicity of the molecules and also the aggregate morphologies resulting from how dendritic OEGs are wrapped around the aggregates. Both photo-irradiation-mediated isomerization of the spiropyran moieties and thermally mediated dehydration and collapse of the dendritic OEGs influence the amphiphilicity of these DSPs and their solvation by water, leading to varied driving forces for their assembly. NMR, circular dichroism (CD) and fluorescence spectroscopy techniques, as well as DLS and AFM techniques are combined to follow the supramolecular assembly and illustrate the aggregation mechanism. All experimental results demonstrate that the reversible chirality of the aggregates originates from the balance between dendritic OEGs and spiropyran moieties against water solvation.