Designing of Rewritable Paper by Hydrochromic Donor–Acceptor Stenhouse Adducts

Investigation of developed photoactive security inks and anticounterfeiting technologies in recent years indicates significant challenges for future of this research area, such as increase of security, fast responsivity, and facile authentication. Here, amine-functionalized latex nanoparticles were synthesized by emulsion copolymerization of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Size of the latex nanoparticles was increased as a function of poly(dimethylaminoethyl acrylate) (PDMAEMA) contents, and also a decrease of particle size was obtained in response to an increase of temperature from 25 to 70 °C, above the lower critical solution temperature (LCST) of PDMAEMA. Surface physical modification of the functional latex nanoparticle with spiropyran photoswitches led to the development of anticounterfeiting nanoinks that have multilevel security and photochromic/fluorescence properties with a higher intensity and also brightness. The photoluminescent nanoinks were made of spiropyran latex nanoparticles and used for printing of the encoded optical security tags on cellulosic papers and banknotes. The results displayed that an increase of the particle size above 100 nm and an increase of the PDMAEMA contents led to a remarkable decrease of printability, fluorescent emission, brightness, intensity of photochromism, and also resolution of the printed security tags. As a significant advantage of the developed security inks, the printed security tags could be authenticated easily and fast upon sunlight irradiation by means of photochromism. The responsivity of encoded tags from the invisible to visible state is immediate upon sunlight irradiation for some seconds, whose intensity of coloration is appropriate and detectable clearly by naked eyes. The security anticounterfeiting inks based on spiropyran with multilevel security have been reported for the first time for applying in printing of encoded security tags on cellulosic papers, banknotes, and other documents, where the printed marks are detectable on sunlight exposure.

Section: Resultsmentioning

confidence: 99%

Photoluminescent Nanoinks with Multilevel Security for Quick Authentication of Encoded Optical Tags by Sunlight: Effective Physicochemical Parameters on Responsivity, Printability, and Brightness

Abdollahi

Dashti

2021

“…Functionalized chromogenic materials with reversible color switching in response to external physical or chemical stimuli are highly attractive in numerous application fields including rewritable media, encryption, − sensors, security printing, and so on. − Especially, as rewritable information storage media, the stimulus-responsive chromogenic systems are promising in developing rewritable paper, − which opens new pathways to alleviate natural resources exhaustion induced by traditional paper consumption. − To date, ingenious design and fabrication of rewritable paper featuring excellent rewriting performance have been achieved via introduction of inorganic materials, organic compounds, and organic/inorganic hybrid materials. For example, Huang et al have synthesized two hybrid chloroantimonates(III) with thermally controlled reversible luminescent switching for the fabrication of laser-printable rewritable photoluminescent paper .…”

Section: Introductionmentioning

confidence: 99%

Robust Scalable-Manufactured Smart Fabric Surfaces Based on Azobenzene-Containing Maleimide Copolymers for Rewritable Information Storage and Hydrogen Fluoride Visual Sensor

Zhai

Fang

Liu

et al. 2021

Functionalized materials with reversible color switching are highly attractive in many application fields, especially as rewritable media for information storage. It is critical yet challenging to develop a cost-effective strategy for the fabrication of stimulus-responsive chromogenic systems. Herein, we present a versatile dip-coating approach to fabricate robust smart textile with acid/base-driven chromotropic capability. Owing to the introduction of novel maleimide-based copolymers bearing azobenzene derivative moieties, smart textiles possess rapid color switching between yellow and orange-red, which is triggered by acid–base stimulations with the resulting reversible protonation/deprotonation of maleimide moieties. As a proof of concept of the application of the smart textile for high-performance rewritable media, various rewritable elaborate patterns can be fast trifluoroacetic acid-printed/triethylamine-erased (within 20 s) with excellent cycling stability and long legible duration (>30 days). Meanwhile, the smart textile can be employed as a visual sensor for the detection of hydrogen fluoride gas leakage. It is highlighted that the as-prepared robust smart textiles with superhydrophobic surfaces have excellent antifouling properties and chemical/mechanical stabilities, which can tolerate harsh environmental conditions and repetitive mechanical deformation. The robust smart textiles with simple low-cost large-scale production may find more advanced potential applications besides information storage and sensors demonstrated.

“…Because paper has the characteristics of flexibility, foldability, recyclability, biodegradability, and low cost, it is very promising to be developed as functional composites for specific applications . Examples of emerging paper-based functional composites include microfluidic devices, − energy storage devices, − sensors, − rewritable paper, − superhydrophobic paper, − electronic paper, − and so forth. The functions of these composites may overlap each other, and, sometimes, paper pretreatment is required to facilitate processing.…”

Section: Introductionmentioning

confidence: 99%

Eco-Friendly Superhydrophobic Composites with Thermostability, UV Resistance, and Coating Transparency

Wan

Zhu

et al. 2021

Despite the market demand for biofiber assemblies endowed with superhydrophobicity being huge, the current approaches to their production are complicated, time-consuming, and even pose a serious threat to the environment. Here, we report a simple surface treatment strategy to prepare environmentally friendly superhydrophobic biofiber composites. The obtained samples have certain UV resistance properties, which are mainly determined by the titanium dioxide (TiO2) dosage. Additionally, the sample has excellent thermal stability, and the contact angle is maintained at 153.26° after heat treatment at 140 °C for 1 h. Quite encouragingly, thermal annealing of samples can transform translucent coatings into transparent structures and increase the tensile strength. The results also showed that this strategy could be integrated into the mass production process of other biofiber components as coating, such as coated paper, pulp boards, cotton gauzes, tissues, and so forth. Due to the facile preparation and environment-friendliness, this sustainable paper-based product can be used in diversified applications: packaging and storage of liquid food, protection of ancient books, UV- and rain-proof materials, and teaching demonstrations relevant to bionics, among others.