Synthesis And Applications Of Surfactants Containing An Azobenzene Motif

With good photo stability,azobenzenes show reversible trans-cis isomerization under UV and Vis light irradiations.The excellent photochromic property makes azobenzenes very attractive in the related studies on chemosensors,polymers,materials,biomolecules and nano devices.Herein,we synthesized two kinds of double-chain ammonium surfactants containing an azobenzene motif,which were applied into the selective detection of mercury as chemosensor and synthesis of DNA thermotropic liquid crystals?TLCs?.The existence of PEG chain improved their water solubility,while the other chain is linear-or T-type aliphatic chain containing the azobenzene motif.With completely water-solubility,the linear azobenzene compound,founctioning as chemical sensor for the selective detection of Hg²⁺,favored the formation of the trans state with the presence of Hg²⁺.The azobenzene chemosensor shows characteristic UV-Vis signal in the band around 240 nm for Hg²⁺in wide pH range,which also shows good tolerance to various metal ions and photoirradiation.The synthesized T-type azobenzene surfactant was used for the preparation of photochromic DNA TLC with double stranded DNA.Upon UV light irradiation,azobenzene isomerizes from trans state to cis state,leading to the liquid crystal-isotropic phase change of the DNA TLC.Considering the good biodegradability of biomacromolecules,this new type of DNA TLC would be an alternative for the drug delivery materials.Finally,we synthesized three azobenzene surfactants with different head substituents,and investigated their phase change properties.Upon comparisons with phase change temperatures before and after UV irradiation,the synthesized three surfactants exhibit different light-and thermo-responsive properties.These observations would facilitate the azobenzene related studies on materials science.