Halogen-Assisted Piezochromic Supramolecular Assemblies for Versatile Haptic Memory

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.