Reversible colour changes of binary films composed of azobenzene-based amorphous molecular materials and p-toluene sulfonic acid in response to exhaled breath

Abstract

Binary films composed of azobenzene-based amorphous molecular materials and p-toluene sulfonic acid were found to exhibit drastic and reversible colour change when we breathed onto their films.

Reversible Change in Fluorescent Color of Moisture‐sensitive Binary Films of 4‐[Bis(4‐methylphenyl)amino]benzylideneaniline with Organic Acids

“…In addition to these single films, amorphous molecular materials can be form homogeneous and/or phase‐separated films with other materials. We have recently been performing studies of such binary systems with smart functions [5–7] . Among them, we have reported that the binary films of aminoazobenzene‐based amorphous molecular materials with organic acids exhibited drastic and reversible color changes in response to moisture [6] .…”

“…We have recently been performing studies of such binary systems with smart functions. [5][6][7] Among them, we have reported that the binary films of aminoazobenzene-based amorphous molecular materials with organic acids exhibited drastic and reversible color changes in response to moisture. [6] It was suggested that the phenomena were due to protonation to the aminoazobenzene caused by the organic acid and deprotonation affected by moisture and that the acidity levels and concentrations of the organic acids were important factors affecting the color of the film and its response to moisture.…”

“…[5][6][7] Among them, we have reported that the binary films of aminoazobenzene-based amorphous molecular materials with organic acids exhibited drastic and reversible color changes in response to moisture. [6] It was suggested that the phenomena were due to protonation to the aminoazobenzene caused by the organic acid and deprotonation affected by moisture and that the acidity levels and concentrations of the organic acids were important factors affecting the color of the film and its response to moisture. In addition to such binary films that exhibited reversible change in object colors, we have created novel moisture-sensitive binary films composed of diarylaminobenzaldehyde-based fluorescent amorphous molecular materials with p-toluene sulfonic acid (TsOH) that exhibited OFF-ON switching of fluorescence in response to moisture, the fluorescence emission being quenched at ambient dry atmosphere but enhanced under wet condition.…”

Modulation of Emission Intensities of Binary Films Composed of Fluorescent Amorphous Molecular Materials and p‐Toluenesulfonic Acid in Response to Exhaled Breath

“…We have previously reported that binary films of amorphous molecular materials based on 4-(diarylamino)azobenzenes with TsOH exhibited reversible color changes by breathing onto their films and concluded that protonation and deprotonation for the 4-(diarylamino)azobenzenes took place in the binary films corresponding to change in surrounding humidity. [8] Based on the similar consideration, present phenomena of reversible emission modulation of BMABA-TsOH film shown in Fig. 1 could be understood as follows.…”

Emission Properties of Hybrid Films of Benzylideneaniline-based Amorphous Molecular Materials with Organic Acids

“…For example, we have reported that spincoated films of diarylaminobenzaldehyde-based emitting amorphous molecular materials exhibited vapochromic emission [11]. In addition to such materials with single component systems, we have recently been studying the creation of hybrid systems of amorphous molecular materials with other materials exhibiting smart functions [13][14][15][16][17][18][19][20][21][22][23]. We have reported that the hybrid films of aminoazobenzene-based amorphous molecular materials with organic acids exhibited drastic and reversible color changes in response to moisture [20].…”