In this report, we designed surfaces with reversible green-light-switched wettability via donor−acceptor Stenhouse adducts (DASAs). Photoresponsive micro/nanoparticles were prepared by coating the surfaces of silica micro/nanoparticles with polydopamine and then postmodifying with DASA molecules. Then, the particles were immobilized on a glass substrate surfaces either with double-sided adhesive tape or cross-linking poly-(dimethylsiloxane). Silica micro/nanoparticles with various diameters (0.2, 2.5, and 85 μm) were used to fabricate the photoresponsive surface. Green light irradiation switches the hydrophobic linear DASA to a hydrophilic cyclic isomer, which further increases the wettability and contact angle hysteresis on the surface. On the other hand, heating (100 °C) induces the cyclic-to-linear isomerization of DASA molecules and switches the surface back to hydrophobic. The wettability of the DASA-modified surface is reversible under alternate green light irradiation and heating.
Photoresponsive materials show the superiorities to be controlled by light in a non-contact, efficient and precise manner, which are therefore attractive in the fields of therapy, pharmacology, semiconductor engineering and...
Logic‐in‐memory devices are a promising and powerful approach to realize data processing and storage driven by electrical bias. Here, an innovative strategy is reported to achieve the multistage photomodulation of 2D logic‐in‐memory devices, which is realized by controlling the photoisomerization of donor–acceptor Stenhouse adducts (DASAs) on the surface of graphene. Alkyl chains with various carbon spacer lengths (n = 1, 5, 11, and 17) are introduced onto DASAs to optimize the organic–inorganic interfaces: 1) Prolonging the carbon spacers weakens the intermolecular aggregation and promotes isomerization in the solid state. 2) Too long alkyl chains induce crystallization on the surface and hinder the photoisomerization. Density functional theory calculation indicates that the photoisomerization of DASAs on the graphene surface is thermodynamically promoted by increasing the carbon spacer lengths. The 2D logic‐in‐memory devices are fabricated by assembling DASAs onto the surface. Green light irradiation increases the drain–source current (Ids) of the devices, while heat triggers a reversed transfer. The multistage photomodulation is achieved by well‐controlling the irradiation time and intensity. The strategy based on the dynamic control of 2D electronics by light integrates molecular programmability into the next generation of nanoelectronics.
Controlling the multistage photoresponsivity remains a challenge, in part, due to the spontaneous tautomerization between isomers. Herein, we present a strategy to access three independent states (linear, cyclic keto, and cyclic enolate) of crown ether (CE)-substituted donor− acceptor Stenhouse adducts (DASAs) by limiting the tautomerization of the closed isomers. The linear−cyclic keto isomerization is reversibly triggered by treatment with metal ions (Na + or K + ) and CE, while the linear−cyclic enolate isomerization is induced by green light and heat. Density functional theory and molecular dynamics calculation results suggest that the steric effect and supramolecular interaction between the electron-donating and electron-withdrawing moieties play an important role in hindering the tautomerization between cyclic keto and cyclic enolate DASA-CE. The strategy to influence key steps in the photoswitching process inspires well-controlled multistage isomerization of photoresponsive molecules.
Postpolymerization
modification using “click” reactions
has been proven to be a powerful method to build functional polymers,
but the way to construct dynamic functional polymers remains challenging.
In this work, CC/CN dynamic exchange reaction between
Meldrum’s acid condensate and aldimine was employed to establish
an efficient dynamic PPM method. Under the condition of catalyst free
and room temperature, the conversion of PPM based on CC/CN
dynamic exchange reaction can be up to more than 90%. Furthermore,
reactive polymer coatings for in situ generating
dyes with different absorbance wavelengths (λmax =
360–605 nm) and rewritable fluorescent papers were successfully
developed by using dynamic PPM to tune the electron donor−π-acceptor
structures in MA condensates on polymers.
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