The Special “Morse Code” between Solvent Polarity and Morphology Flexibility in a POSS–Dendrimer Supramolecular System

Abstract

An amazing phenomenon of the relative magnitude of modulus of two liquid-crystal( LC) gels is found inverted under/abovet heir phase transition temperature T LC-iso , which is further provedt ob ecaused by their diversem orphologyf lexibility.B yt esting the polarity of two LCs, gelator POSS-G1-Boc (POSS = polyhedral oligomeric silsesquioxane) was discovered to self-assemble into more flexible structures in ar elatively low polar LC, whereasm ore rigid ones are formed in higherp olar LC. Hence, af itting functiont oc onnect morphology flexibility with solvent polarityw as established,w hich can even be generalized to an umber of common solvents. Experimental observations and coarsegrained molecular dynamics simulations revealed that solvent polarity mirrors a" Morsec ode", with each "code" corresponding to aspecificm orphologyf lexibility.

Contradiction or Unity? Thermally Stable Fluorescent Probe for In Situ Fast Identification of Self-sort or Co-assembly of Multicomponent Gelators with Sensitive Properties

“…On the one hand, incubation at high temperature is a common experimental method used in supramolecular gel preparation to help the gelators dissolve in the solvent and cool to form gels. − Because multicomponent gels have multiple gel–sol phase transition temperatures ( T gel‑sol ), an ideal fluorescent probe should keep thermal stability in a wide temperature range, and the PL intensity should not change before adding multicomponent gelators. On the other hand, the fluorescent probe should sensitively detect the morphological difference of multicomponent gel networks by their self-assembly properties and the resultant PL intensity changes, but it is difficult to maintain thermal stability due to the principle that supramolecular self-assembly changes with temperature. − Therefore, the contradictory relationship between thermal stability and sensitivity results in a few fluorescent probes fulfills the above two properties and hence they are applied in multicomponent gel networks. Considering the mechanism of most fluorescent probe molecules with excellent self-assembly properties reported until now, neither aggregation-caused quenching (ACQ) nor aggregation-induced emission (AIE) molecules could show thermally stable properties.…”

“…Inspired by the strong self-assembly ability of the three-dimensional polyhedral oligomeric silsesquioxane (3D POSS) core dendrimer reported by our group, − ,, we synthesized the multiple peripheral functional group tetraphenylethene (TPE) modified well-defined cubic core (POSS) 3D dendrimer (POSS-TPE, Figure a) . The 3D molecule structure with explicit geometry and symmetry has better self-assembly performance and thermally stable assembly structure than ordinary two-dimensional (2D) molecules in a wide temperature range. ,, The steric hindrance in the self-assembly structure of POSS-TPE restricts the intramolecular rotation of phenyl rings in the TPE, leading to monomer emission. − Thus, the PL intensity of monomer emission can change sensitively with the self-assembly structure as well as keeps steady when the self-assembly structure reaches a thermodynamic equilibrium state.…”

“…Inspired by the strong self-assembly ability of the threedimensional polyhedral oligomeric silsesquioxane (3D POSS) core dendrimer reported by our group, [14][15][16][17]19,22 we synthesized the multiple peripheral functional group tetraphenylethene (TPE) modified well-defined cubic core (POSS) 3D dendrimer (POSS-TPE, Figure 1a). 23 The 3D molecule structure with explicit geometry and symmetry has better self-assembly performance and thermally stable assembly structure than ordinary two-dimensional (2D) molecules in a wide temperature range.…”