Synthesis and Optical Properties of Polystyrene Bearing Stilbenoid Side Chains

Abstract

Four series of random graft copolymers with stilbenoid side chains on a polystyrene (PS) backbone were synthesized, and their optical properties were compared with blends of a series of model compounds in PS. The graft loading (5, 15, and 25 mol %), the type of link to the polymer backbone ("ether" or "direct"), and the number of methoxy groups substituted on the stilbene moiety were systematically varied. Absorption, emission, and time-resolved photoluminescence (PL) properties are presented for the compounds in solution and as spin-coated films, and relative quantum yields have been determined. Mixed monomer/excimer emission was found to be the characteristic emission for all grafts, while the reversibility of the excimer formation seems to vary for the different grafts. In the blends the miscibility of the model compounds is quite different: the 4-methoxystilbene/PS system readily forms aggregates and crystallites, whereas the 3,4,5-trimethoxy-4′-methylstilbene/PS system forms uniform mixtures showing excimer-type emission. The PL efficiencies decreased with concentration in all cases where excimeric emission was found. For the blend containing 4-methoxystilbene, however, the PL efficiency increased with concentration.

Aromaticity Effects on the Profiles of the Lowest Triplet‐State Potential‐Energy Surfaces for Rotation about the CC Bonds of Olefins with Five‐Membered Ring Substituents: An Example of the Impact of Baird’s Rule

“…[1][2][3][4][5][6][7][8][9][10][11] Many functional materials as well as molecular switches and motors are designed on the basis of photoinduced molecular interconversion. [12,13] For example, sterically overcrowded alkenes constitute the core of the chiroptical molecular switches and unidirectional molecular rotary motors of Feringa and co-workers. [14] The Z/E photoisomerizations of alkenes and azobenzenes have also been exploited in molecular electronics to optically switch electron transport [15][16][17] and to photomechanically control the electronic properties of linear p-conjugated compounds.…”

The photochemistry of some main chain liquid crystalline 4,4′-stilbene dicarboxylate polyesters

“…32 Fluorescence spectra of films of several other polymers show only weak structure. 33 Aerts et al 34 used time-resolved fluorescence spectroscopy to observe two types of emissive aggregates in a stilbene side-chain substituted polystyrene. One species was observed in the 0 to 500 ps time window, the other (red shifted) in a 1.5 to 4 ns time window.…”

Final LDRD report : advanced plastic scintillators for neutron detection.

“…2,3,4,5 In those systems, it was found that the tSB functional group retained the fluorescence properties of the monomer, and that emission resulted from a fluorescent dimer. Most interesting, however, was the observation of Karasz and coworkers that the tSB-functionalized polymer absorbed energy at solution concentrations where the monomer did not.…”