Syntheses And Photochemical Properties Of Phenylnaphthalene Derivatives

The polymer with photosensitive group can generate axis-selectivephotoreaction under the linearly polarized ultraviolet light (LPUV), which formsanchoring force to induce orientation of liquid crystal molecule. When thefunctional molecular liquid crystal doped into polymer film, and then annealedin the LC temperature range, the whole molecules arranged along the directionof anchor point for the self-assemble of molecule. Therefore, they formeddifferent orientation of molecules between the exposed area and unexposedarea, and generated visual discrepancies. This technique was applied ininformation recording. By the photoreaction of function molecule under LPUVmade the order fixed at other temperature, and it got the same mobility at roomtemperature as LC temperature.In this paper, four kinds of compounds were synthesized with phenylnaphthalene core group and different end groups. They were2-(hexyloxy)-6-(4-(hexyloxy)phenyl)naphthalene(M1)、ethyl6-(4-(6-((6-ethoxy-6-oxohexyl)oxy)naphthalen-2-yl)phenoxy)hexanoate(M2)、6-(4-(6-((5-carboxypentyl)oxy)naphthalene-2-yl)phenoxy)hexanoic acid(M3) and allyl6-(4-(6-((6-(allyloxy)-6-oxohexyl)oxy)naphthalen-2-yl)phenoxy)hexanoate(M4), respectively. The structures ofthese compounds were characterized by FT-IR and1HNMR spectra. Theirliquid crystal properties were tested by differential scanning calorimetry (DSC)and hot stage polarizing microscope (POM). The charge carrier mobility couldbe determined by the time of flight (TOF). The orientation of the molecule M4could be tested under the annealing treatment. A polymer with photosensitivegroup of Poly[7-((6-(Methacryloyloxy)hexyl)oxy)coumarin] was synthesized, itsphotoreaction performance and the photo orientation performance of themolecule doped in the polymer also were studied.The results showed that the four molecules had liquid crystal and charge carrier transport property. And the difference of terminal group had a certainimpact on the range of liquid crystal phase and charge carrier mobility. M1exhibited ambipolar transport and the range of mobility was10-4~10-2cm2/v·s,the carrier mobility transport displayed electric field and temperaturedependent. M2only exhibited hole transport, and the mobility was about10-4cm2/v·s, which appeared to be both independent of electric field andtemperature. M4exhibited electron transport at120℃, and the mobility wasabout10-3cm2/v·s. However, after exposed at annealing temperature, theorderly degrees of M4could be fixed at room temperature and got the samecarrier charge mobility as LC temperature. For the doping, when the exposeenergy was480mJ/cm2and the annealing temperature at100℃，the opticalanisotropy arrived maximum,△Amax=-0.014.