Diacetylene-Functionalized Dendrons: Self-Assembled and Photopolymerized Three-Dimensional Networks for Advanced Self-Healing and Wringing Soft Materials

Abstract

The physical properties of supramolecular soft materials strongly depend on the molecular packing structures constructed by thermodynamically and kinetically controlled molecular self-assembly. To investigate the relationship between molecular function and selfassembled molecular packing structure, a series of diacetylene (DA)-based supramolecules was synthesized by chemically connecting flexible dendrons to DA with amide (aDA−D) or ester (eDA−D) functions. The three-dimensional (3D) organogel network of amide-functionalized aDA−D was prepared in both polar and nonpolar solvents due to the intermolecular hydrogen bonding. 3D networks of aDA−D can be further stabilized by topochemical photopolymerization. The self-healing behavior of aDA−D was observed in the sheet-like structure formed in n-dodecane by the hydrophobic interaction between the gelator and solvent. The wringing behavior of aDA−D was also demonstrated using the dynamic interaction of amide function with n-butanol solvent. Kinetically controlled and photostabilized 3D networks can be a key component from biomedical devices to soft robotic applications.

Morphological Transitions of a Photoswitchable Aramid Amphiphile Nanostructure

“…Diffraction on the subnanometer length scale provides local molecular packing information, so we perform 1D wide-angle X-ray diffraction (WAXD) on lyophilized samples of compound 2 nanostructures to elucidate this effect. 46 Weakening and broadening of sharp reflection peaks after UVA irradiation indicate that long-range molecular and shortrange positional orders are partially disrupted compared to the trans state (Figure S23). To maintain favorable interactions, we infer that the hydrophilic cationic head groups orient toward their aqueous environment, inducing curvature to the assembly.…”

“…Upon UVA irradiation for conversion of 2 to the cis state, the molecules take on a bent-shape geometry and flexible conformation, resulting in local reorganization to compensate for space requirements. Diffraction on the subnanometer length scale provides local molecular packing information, so we perform 1D wide-angle X-ray diffraction (WAXD) on lyophilized samples of compound 2 nanostructures to elucidate this effect . Weakening and broadening of sharp reflection peaks after UVA irradiation indicate that long-range molecular and short-range positional orders are partially disrupted compared to the trans state (Figure S23).…”

Fluorescent litmus film for detecting acid vapors: free-standing and robust AIE sensing film fabricated by photopolymerization of self-assembled hierarchical triphenylamine-based gelators

“…2b). 47 This blueshifting toward the lower wavelength indicates that intermolecular hydrogen bonding of the amide function is enhanced as a main driving force. In WAXD pattern (Fig.…”

Stimuli responsive dynamic transformations in supramolecular gels

“…181 Recently, the Jeong group illustrated thermal behaviour of a diacetylene-functionalized dendron in n-butanol. 182 The dendron molecules contain amide functionalities for hydrogen bonding, long alkyl chains for van der Waals interactions and a diacetylene core as a photoresponsive unit. Initially, a turbid organogel was formed by the self-assembly of the molecules involving hydrogen bonding and hydrophobic interactions.…”