Multi-stimuli-responsive color/fluorescence dual-switching behavior of a hyperbranched polyamidoamine bearing viologen and adamantane units

Multi-stimulus-responsive materials have been intensively explored due to their wide applications of sensors, controlled drug release, and intelligent devices. However, color/fluorescence dual-switching response to the multiple external triggers has rarely been reported. We present here the multi-stimuli-responsive color/fluorescence dual-switching behavior of a novel hyperbranched polyamidoamine bearing viologen and adamantane units through one-pot Michael addition polymerization coupled with terminal modification tactic. This fascinating color/fluorescence dual-switching behavior is originated from conformation change (protonation/deprotonation of tertiary amines), reversible aggregation/de-aggregation (hydrophilic/hydrophobic balance modulation by adamantanes), and molecular structure transition (redox of viologens) within a polymer scaffold upon multiple environmental stimuli of pH value, heat, and electric potential. This delicate molecular design provides an alternative avenue toward a new class of smart, adaptive, and responsive polymers.