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Reversible Ion‐Conducting Switch in a Novel Single‐Ion Supramolecular Hydrogel Enabled by Photoresponsive Host–Guest Molecular Recognition
Author(s) -
Wang Hu,
Zhu Chao Nan,
Zeng Hong,
Ji Xiaofan,
Xie Tao,
Yan Xuzhou,
Wu Zi Liang,
Huang Feihe
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201807328
Subject(s) - azobenzene , materials science , supramolecular chemistry , ionic bonding , ionic liquid , ionic conductivity , isomerization , photochemistry , ion , nanotechnology , molecule , chemistry , polymer , electrolyte , organic chemistry , electrode , catalysis , composite material
A novel ion‐conducting supramolecular hydrogel with reversible photoconductive properties in which the azobenzene motif, α‐cyclodextrin (α‐CD), and ionic liquid are grafted onto the gel matrix is reported. Host–guest interactions with different association constants between α‐CD and azobenzene or the anionic part of the ionic liquid can be readily tuned by photoinduced trans–cis isomerization of the azobenzene unit. When irradiated by 365 nm light, α‐CD prefers to form a complex with the anionic part of the ionic liquid, resulting in decreased ionic mobility and thus high resistance of the hydrogel. However, under 420 nm light irradiation, a more stable complex is again formed between α‐CD and trans ‐azobenzene, thereby releasing the bound anions to regenerate the low‐resistive hydrogel. As such, remote control of the ionic conductivity of the hydrogel is realized by simple host–guest chemistry. With the incorporation of a logic gate, this hydrogel is able to reversibly switch an electric circuit on and off by light irradiation with certain wavelengths. The concept of photoswitchable ionic conductivity of a hydrogel mediated by competitive molecular recognition is potentially promising toward the fabrication of optoelectronic devices and applications in bioelectronic technology.