Halogen-Assisted Piezochromic Supramolecular Assemblies for Versatile Haptic Memory

TLDR

Sensory memory records external stimuli, yet existing tactile sensors suffer from complex operation and poor retention, creating a need for simple, highly sensitive haptic memory materials. The study develops two halogen‑bond‑assisted piezochromic assemblies for haptic memory. Halogen bonding stabilizes the network, expands the piezofluorescent range, and increases sensory sensitivity. The assemblies retain color change after stimulus removal, recover reversibly with mild heating, and enhance overall haptic memory performance.

Abstract

Sensory memory is capable of recording information and giving feedback based on external stimuli. Haptic memory in particular can retain the sensation of the interaction between the human body and the environment and help humans to describe the physical quantities in their environment and manipulate objects in daily activities. Although sensitive and accurate tactile sensors have been produced on optical and electronic devices, their rigorous operation and equipment requirements seriously limit their further applicability. In addition, their poor retainability after the removal of external stimuli also warrants further improvements. Thus, haptic memory materials, having simple structures and high sensitivity, are highly desired. Herein, we successfully developed two piezochromic assemblies assisted by halogen bonding for haptic memory. The halogen bond not only contributes to the fabrication of the network and enhances integrative stability but also broadens the natural piezofluorescent range, thus promoting sensory sensitivity. Moreover, the colorimetric change of the assemblies could be well-retained after the stimulus was removed. Upon mild heating treatment, the piezochromic response could be recovered to its original state, confirming the recyclability of this haptic memory material for use in practical applications. The present work enriches the library of piezochromic materials with enhanced performance for haptic memory.