Distinctive Colorimetric Response of Benzaldehyde Substituted Polydiacetylene Vesicle to Temperature, pH, and Organic Amines

Abstract

Here, a benzaldehyde substituted diacetylene vesicle formed through a self-assembly strategy in water is reported. Under UV irradiation, conjugated polydiacetylene (PDA) could be generated in the blue phase by 1,4-addition topopolymerization. Furthermore, this newly developed PDA vesicle displays distinctive colorimetric response to triple stimuli, including temperature, pH, and organic amines. Specifically, a clear blue-to-purple-to-red chromatic transition is observed for the PDA vesicle upon a gradient heating procedure from 25 to 75 °C. Although no obvious colorimetric changes happen when the PDA vesicle is exposed to acidic environments, it gradually turns into red color in alkaline aqueous solution or atmosphere with increasing pH values. More interestingly, this PDA vesicle can serve as an excellent sensor to distinguish some typical aliphatic/aromatic amines based on its different colorimetric and morphologic transformation behaviors. It is suggested that the incorporated benzaldehyde head group in PDA plays an essential role for the resulting responsiveness to the various environmental stimuli. As the preparation method is simple and straightforward, the novel PDA vesicle introduced here holds great potential as a promising sensor with the naked eye.

Structure and stability of polydiacetylene membrane systems: Molecular dynamics simulation studies

“…By introducing appropriate functional groups in the monomeric unit of PDAs, they can be engineered to have new sensing capabilities for new sensing materials or environmental stimuli. [7,8,[26][27][28][29][30][31][32] Especially, PDAs with a lysine head group (PDA-LYS) show interesting colorimetric responses in the presence of surfactants. [17,33] First of all, they respond only to cationic surfactants such as dodecyl(trimethyl)azanium bromide (DTAB), not to anionic surfactants.…”