Tough, Transparent, and Anti-Freezing Nanocomposite Organohydrogels with Photochromic Properties

Abstract

Poor mechanical properties and freezing at low temperatures of traditional photochromic hydrogels limit their applications. Here, a novel type of photochromic nanocomposite organohydrogels (NC OGHs) by adding tungsten oxide nanoparticles was prepared by a simple one-pot method. The photochromic NC OGHs demonstrated excellent integrated properties, including high transparency, high mechanical properties, low-temperature resistance, anti-dehydration, rewrite capability, and UV blocking ability. In addition, the degree of coloration of NC OGHs could be precisely controlled by UV irradiation, and the bleaching process could be controlled by the temperature and atmosphere. Besides flexible optical information storage devices and optical filters, these photochromic NC OGHs were also used for smart windows in both room temperature and cold environments. The work provides a new insight into photochromic organohydrogels.

Facile Preparation of Drug-Releasing Supramolecular Hydrogel for Preventing Postoperative Peritoneal Adhesion

“…The optimized structure reveals the obvious binding between PVA and these three drugs. Obviously, the greater the number of phenolic hydroxyl groups, the more likely they are to form hydrogen bonds. − Polyhydroxy compounds are more likely to form H-bonds with PVA, especially with o -dihydroxy groups . As the number of phenolic hydroxyl groups increases, the structure of the PVA/hydrophobic drug gradually becomes more complex, and it may even generate multiple hydrogen bonds like PVA/MYR.…”

Graphene-Based Tunable Coloration Film through Intercalation

“…9 Yang et al provided photochromic nanocomposite organohydrogels with high transparency, excellent strength, and 60 s response time. 10 Meanwhile, structural color is another important approach to produce high-resolution colors with a physical structure. 12,13 By designing nanostructures such as nanowires, 14 gratings, 15 and disk-hole coupling 16 with suitable geometrical parameters, the desired color can be acquired from reflecting or scattering light through periodic arrays or individual resonators.…”

“…Organic pigments including printing inks and paints are the convenient coloration materials used for color generation. However, it still has some unavoidable drawbacks such as insufficient resolution, , poor stability, and difficult tunability. , Thus, the tuning methods such as electrochromic, thermochromic, and photochromic are proposed for dynamic color manipulation. − Liu et al developed a nontoxic chlorophenol red–water thermochromic system for clear and reversible color display . Yang et al provided photochromic nanocomposite organohydrogels with high transparency, excellent strength, and 60 s response time .…”

“…However, it still has some unavoidable drawbacks such as insufficient resolution, , poor stability, and difficult tunability. , Thus, the tuning methods such as electrochromic, thermochromic, and photochromic are proposed for dynamic color manipulation. − Liu et al developed a nontoxic chlorophenol red–water thermochromic system for clear and reversible color display . Yang et al provided photochromic nanocomposite organohydrogels with high transparency, excellent strength, and 60 s response time . Meanwhile, structural color is another important approach to produce high-resolution colors with a physical structure. , By designing nanostructures such as nanowires, gratings, and disk-hole coupling with suitable geometrical parameters, the desired color can be acquired from reflecting or scattering light through periodic arrays or individual resonators. , By combining advantages of the structural color and smart materials such as electrochromic materials, many researchers have shown excellent works about color tuning. − For example, Arsenault et al reported an electrical control method to control photonic crystals to fabricate a full-color display with 1–2 s response time, and its cycling stability is excellent .…”

Synthesis and fabrication of gelatin-based elastomeric hydrogels through cosolvent-induced polymer restructuring

“… 42,43 However, a further increase in THF proportion has resulted in phase separation due to incompatibility of gelatin in water–THF cosolvent and has been observed earlier in case of water–ethanol cosolvent, due to solvophobic interactions between gelatin and free THF molecules. 15,23 Incubation of samples at 50% v/v THF caused sedimentation, resulting in a clear supernatant and a sedimented film. This happened perhaps due to coalescence of coacervates/aggregates present in water–THF cosolvent confirmed by SEM analysis of freeze–dried samples shown in the next section.…”