Versatile Hydrochromic Fluorescent Materials Based On A 1,8-Naphthalimide Integrated Fluorophore-Receptor System

Atmospheric moisture uptake by materials of varying hygroscopicity considerably change their physicochemical properties and herein has long time been a hot point in the development and manufacture of all kinds of products.Especially,hydrochromic materials,which are scalable,easily processed from their raw materials,exhibit pointof-use versatility,and are sufficiently sensitive to alteration in water amounts,have been successfully used as sensors,paint,and coating industry.In this thesis,I developed a series of integrated fluorophore-receptor systems that exhibit reversible fluorescence hydrochromism in the solid state responding to the changes in atmospheric relative humidity.1,8-Naphthhalimide fluorophore,pyridinium acceptor,and its anion are the three components of this functional system,which serves as a water-sensitive receptor capable of engaging the emissive unit by way of excited state charge transfer.Dynamic vapor sorption isotherms provided insight into the amounts of water adsorbed by the solid samples under different relative humidity conditions in order to draw parallel connections with changes in the solid state emission spectra under the same conditions.Agar was introduced into this work to increase the hygroscopicity of the materials and to facilitate their processing into hydrochromic ultra-light agar-based hygroscopic aerogels.This modification increased material's hydrochromic sensitivity,effectively decreasing their critical relative humidity from ?75% to less than 20% with bathochromic shifts of up to 93 nm.In addition,fluorescent hydrochromic silica gel/carboxymethyl cellulose films and inkjet printer compatible inks were also developed and displayed increased point-of-use versatility.Different kinds of anion products were studied and their solid state emission spectra was recorded in different relative humidities.An obvious bathochromic shift was found in the products which have a strong ability to uptake moisture.This work makes the case for the inclusion of the integrated fluorophore-receptor system as a design principle for the construction of compounds that express aggregation induced emission,and/or aggregation induced emission enhancement in the solid state,and their continued post-synthetic development,and materials processing.