Investigation Of The Synthetic Route Of A Dendritic Polymer Organic Quasicrystal

Quasicrystals have attracted much attention in the field of materials owing to their unique structure and physical properties,organic quasicrystal as a branch of quasicrystal field,however,has been paid attention only in the past decade.Although some organic quasicrystal have been obtained by molecular covalent interactions and synthesis method,only the 12-and 18-fold symmetric organic quasicrystals were found except that FeCOOH can self-assembled into 5-fold symmetrical patterns,i.e.only planer quasicrystals are discoverd.The aim of this study is to synthesize a kind of dendritic polymer,hoping to get a new quasiperiodic phase,such as three-dimensional organic quasicrystals by means of changing the temperature or pressure.In this work,the convergence of synthetic method is used to synthesize the dendritic polymer.The starting materials are 3,4,5-three methyl benzoic acid methyl ester and 1-Bromododecane,to synthesize a series of different end groups and algebras of different type AB₂ dendrimers.The synthesis and purification conditions of these polymers were optimized.The structure and physical properties were characterized by infrared spectroscopy,nuclear magnetic resonance spectroscopy,thermal weight loss spectroscopy,polarized light microscopy.Finally,the synthesis of the branched molecules was analyzed by UV and fluorescence spectra,in order to study the photoluminescence properties.Although organic quasicrystals have not been successfully obtained,a bright transparent crystal PPh₃O in the process is discovered and its crystal structure was confirmed by the single crystal x-ray diffractions.The crystal structure is Orthorhombic P,space group is Pbca.The SEM results show the PPh₃O is needle or flat like.Druing the low temperature test,it is found that the PPh₃O single crystal does not have phase transition down to 150 K.