Photoinduced Proton Transfer between Photoacid and pH‐Sensitive Dyes: Influence Factors and Application for Visible‐Light‐Responsive Rewritable Paper

Abstract

Ink‐free printing based on rewritable paper is an efficient and environmental friendly way to reuse paper, protect resources, and save energy for sustainable development of human society. Among various kinds of rewritable media, light responsive rewritable paper (LRP) is one of the most popular research areas due to its clean and favorable noncontact writing. Visible light is more suitable for LRP for its superior penetration and much less damages to organic molecules than UV light. However, visible‐light‐responsive rewritable paper (VLRP) has only limited successes so far. Herein, a VLRP is newly designed and fabricated based on photoinduced proton transfer (PPT) between photoacid and pH‐sensitive dyes. Success of it is highly benefited from systematical investigation and in‐depth understanding on the key influence factors, such as concentration‐induced undesired isomerization, temperature, humidity, and light intensity, on the PPT and its inverse process. As‐prepared VLRP shows long‐awaited properties, such as, high color contrast and resolution, appropriate legible time of prints, excellent reversibility (>100 cycles), easiness to achieve multicolor prints, and agreeing well with environmental concept of green printing. In addition, study of influence factors on PPT in this work, to some extent, may also help people understand complex photocycle process in biosystem.

Photo‐/Baso‐Chromisms and the Application of a Dual‐Addressable Molecular Switch

“…Filter paper was chosen as as ubstrate, upon which polyethylene glycol (PEG) was loaded to passivate the multihydroxyl of paper (Figure 4a). [48,49] To examine the photochro-mic and basochromic properties of the SP-OX-NO 2 based paper,r eflective UV-vis spectra were measured with an integrating sphere upon exposure to thev isible light or base. Before any stimulation, the magenta paper exhibited ab road reflectance peak at 539 nm, whichw as assigned to the trans MC form of SP-OX-NO 2 (Figure 4b).…”

A Series of Iodoargentates Directed by Solvated Metal Cations Featuring Uptake and Photocatalytic Degradation of Organic Dye Pollutants

“…Organic dyes have been widely employed in the areas of textiles, inks, clothinga nd plastics recently acting as ab asic industrial material. [28][29][30] Unfortunately,t heir temperature-stable naturet ogether with high toxicity makes them to be one of the major environmental pollutants. Untiln ow,m any efforts have been made on the removal of dye pollutantst hat have been thrown to nature with al arge amount.…”

Facile Synthesis and Photoactivity of Merocyanine‐Photoacid Polymers

“…The solid form is often required for material applications. Photoacids have been doped in polymer films for the development of sensors and photochromic materials . Compatibility with the polymer host and leakage of the photoacids are common problems for this approach.…”

“…A large and reversible change of proton concentration can be induced by visible-light irradiation using this type of photoacid. Applications of merocyanine photoacids in energy conversion, [3][4][5] sensor, [6] polymerization, [7] patterning, [8][9][10] nanomaterial, [9,11,12] molecular machine, [13] photochromic materials, [10,[14][15][16] and biomedical [17,18] areas have been reported by our group and other groups.…”

“…Photoacids have been doped in polymer films for the development of sensors [6,19] and photochromic materials. [10,20] Compatibility with the polymer host and leakage of the photoacids are common problems for this approach. Covalently linking photoacids to polymers can improve their compatibility with different media, and avoid the leakage problem.…”