Effects of Chain Parameters on Kinetics of Photochromism in Acrylic–Spiropyran Copolymer Nanoparticles and Their Reversible Optical Data Storage

Abstract

Chemical bonding between photochromic compounds and polymer matrices will induce several consitions such as photostability, photoreversibility, elimination of dye aggregation, and undesirable negative photochromism. In such polymeric systems, the switching rate and photoisomerization are closely dependent on several parameters like chain flexibility, steric restrictions, polarity, and even proticity of the surrounding medium. Here, copolymerization of a synthesized spiropyran-based monomer with butyl acrylate (BA) and methyl methacrylate (MMA) comonomers was carried out with various compositions of MMA and BA through emulsion polymerization, and the corresponding photoisomerization kinetics were studied. Particle sizes and their distributions were analyzed by dynamic light scattering, and morphologies were investigated by scanning and transmission electron microscopic analyses. The results showed the particles are spherical with diameter 62-82 nm. Differential scanning calorimetric thermograms were employed to determine T of the prepared copolymers, which ranged from -23 to 93 °C. The kinetics of photoisomerization was then studied by UV-vis spectroscopy. Finally, a latex containing spiropyran/acrylic copolymer with T of about 0 °C and optimum rate of coloration and decoloration was considered in reversible optical data storage studies due to its fast photochromism and good film-formation properties.

Reversibly Photoswitchable Tristate Fluorescence within a Single Polymeric Nanoparticle

“…Different parameters have been optimized to obtain highly efficient TS-NP: 1) Comonomer. In a previous report, [57] it has been mentioned that the ring-opening speed of spiropyran would be limited by the rigid matrix of polymer nanoparticles. To reduce the restriction of matrices to the switchability of spiropyran in our system, butyl acrylate (BA) that could form soft matrices was used as a comonomer to prepare the nanoparticles and polymer films.…”

Light-switchable anchors on magnetized biomorphic microcarriers

“…9,15 The incorporation of light-switchable molecules into various systems and the development of so-called dynamic materials came into the focus of attention during the last decades. Not only the synthesis of materials for data storage, 16 electronic devices 17 or sensors 18 but also the biological applications of photo-responsive compounds, e.g. in photopharmacology, [19][20][21] have been investigated.…”

Photoactive Polyoxometalate/DASA Covalent Hybrids for Photopolymerization in the Visible Range

“…Until recently, most of the organic photochromic compounds reported in the literature were derived from various classes of molecules, mainly spiropyrans, diarylethenes, fulgides and azobenzenes . These systems, which can be activated by UV light, are of great interest due to their implication in numerous fields such as optical sensors, data storage or molecular logic gates . However, in order to avoid high‐energy UV‐light irradiation, efforts have been focused on the elaboration of reverse photochromes, that is, compounds that can be activated under visible light, as indigos or appropriately functionalized azobenzenes .…”