White-Light-Emitting Supramolecular Polymer Gel Based on β-CD and NDI Host-Guest Inclusion Complex

Abstract

Supramolecular polymer formed by non-covalent interactions between complementary building blocks entraps solvents and develops supramolecular polymer gel. A supramolecular polymer gel was prepared by the heating-cooling cycle of β-cyclodextrin (β-CD) and naphthalenedimide (NDI) solution in N,N-dimethylformamide (DMF). The host-guest inclusion complex of β-CD and NDI 1 containing dodecyl amine forms the supramolecular polymer and gel in DMF. However, β-CD and NDI 2, having glutamic acid, fail to form the supramolecular polymer and gel under the same condition. X-ray crystallography shows that the alkyl chains of NDI 1 are complementary to the hydrophobic cavity of the two β-CD units. From rheology, the storage modulus was approximately 1.5 orders of magnitude larger than the loss modulus, which indicates the physical crosslink and elastic nature of the thermo-responsive gel. FE-SEM images of the supramolecular polymer gel exhibit flake-like morphology and a dense flake network. The flakes developed from the assembly of smaller rods. Photophysical studies show that the host-guest complex formation and gelation have significantly enhanced emission intensity with a new hump at 550 nm. Upon excitation by a 366 nm UV-light, NDI 1 and β-CD gel in DMF shows white light emission. The gel has the potential for the fabrication of organic electronic devices.

Heat-set supramolecular polymer gel and decomposition by guests

“…[37][38][39] So, the effects of adding guest molecules to stearic acid appended L-lysine 40 1 to the thermo-setting gelB systems were investigated. Due to the formation of the supramolecular polymer through host-guest interaction [41][42][43][44] with compound 1 and b-CD, gelB is thermo irreversible. As shown in Table 3, gelB systems were sensitive to the guest molecules.…”

Anion-assisted supramolecular polymerization of luminescent organic π-conjugated chromophores in a moderately polar solvent: tunable nanostructures and their corresponding effects on electronic properties

“…Supramolecular polymers [1][2][3][4] have come to light as a fascinating class of macromolecular systems endowed with dynamic and adaptive nature. [5][6][7][8] Categorically, supramolecular polymers of functional π-conjugated chromophores [9][10][11][12][13] have been investigated extensively in the recent past due to their applications in the area of organic optoelectronic devices. [14][15][16][17][18] A wide range of π-chromophore-based p-and n-type organic semiconductors have been found to form 3D networks of fibers [19][20][21] and act as active materials in organic solar cells and thin film transistors, as reported in the literature.…”