Photoregulated Morphological Transformation of Spiropyran Derivatives Achieving the Tunability of Interfacial Hydrophilicity

Abstract

Regulation of self-assembly morphology is an effective strategy to obtain advanced functional materials with expected properties. However, achieving remarkable morphological transformation by light irradiation is still a challenge. Herein, three simple spiropyran derivatives (SP1, SP2, and SP3) are constructed, achieving different degrees of morphological transformation from nanospheres to hollow tadpole-like structures (SP3), tubular structures (SP2), and microsheets (SP1) after ultraviolet light irradiation. Interestingly, the hollow tadpole-like structures (SP3) can further extend to Y-shaped or T-shaped tubular morphology. In the process, SP1, SP2, and SP3 can be isomerized from a closed-ring form (hydrophobicity) to an open-ring form (hydrophilicity) in different degrees, interacting differently with methanol solvent molecules. The formation of hollow structures or microsheets along with the isomerization of spiropyran derivatives contributes to the adjustment of the hydrophilicity of the interface. Therefore, SP1, SP2, and SP3 with photoregulated morphological transformation show promising applications in tunable interface materials.

Dynamic Anticounterfeiting Through Novel Photochromic Spiropyran-Based Switch@Ln-MOF Composites

“…As the result shows, the characteristic vibration peaks of SP (1512 and 1334 cm –1 correspond to the asymmetric and symmetric stretching vibrations of −NO 2 and 1095 cm –1 belongs to C–O stretching in the SP molecule) were discovered in the FTIR spectra of SP@Eu-MOF (Figure S3). , Thermogravimetric analysis (TGA) can evaluate the structural information and thermal stability of samples. According to the TGA curves shown in Figure S5, it can be seen that the two weight loss stages are the loss of solvent molecules (DMF and H 2 O at 100–200 °C) and ligands (570–660 °C).…”

Disordered Low Molecular Weight Spiropyran Exhibiting Photoregulated Adhesion Ability

“…(Figure 6) Interestingly, the red film gives smaller contact angle of ∼7° than that of purple film, which is resulted from its lower surface roughness (Figure 6. a vs. d ) [30,31] . The red film is originated from the isotropic liquid MC 4 , and the homogeneous composition of planar MC 4 favors the formation of low surface roughness.…”

“…a vs. d). [30,31] The red film is originated from the isotropic liquid MC 4 , and the homogeneous composition of planar MC 4 favors the formation of low surface roughness. While, the purple film is arisen from MC 4 -I&SP 4 -I, of which the heterogeneous composition causes the surface rougher.…”

Photoresponsive reversible self-assembly of rod-coil amphiphiles containing spiropyran groups

“…The aggregates of the small molecules were transformed from nanospheres to hollow tadpole-like structures, tubular structures, and microsheets when exposed to UV light. 34 Razavi et al created a group of amphiphilic block polymers with SP end groups and poly (2-(dimethylamino) ethyl methacrylate) segments in the structure, which imparted them with multi-responsive properties. In water, the polymers self-assemble to form different micelles, and the size of the micelles can be regulated by light, heat, or pH stimulation.…”