An ordered ladder polyester (LPE) was first synthesized through the ladder superstructure (LS) constructed by concerted interactions of hydroxyl- and aramide-based H-bonding and p-terphenyl (TP)-based re-stacking by dehydrochlorination condensation using phosgene (COCl2) as coupling agent. LPE was characterized by GPC, FTIR, NMR, XRD, DSC and AFM. Among them, a distinct image of regularly linear alignment corresponding to the ladder main chain of LPE was first revealed by high-resolution AFM.
A novel soluble and reactive amide-bridged ladderlike polyhydrosiloxane(ALPHS)was first synthesized by an amido H-bonding self-assembled template.ALPHS with molecular weight (?)_n=18300 has very highly ordered ladderlike structure,which was confirmed by a sharp resonance absorption peak of[—Si(H)O_(2/2)]moiety with the half peak width Δ_(1/2)＜0.5 in ^(29)Si-NMR spectrum.Presence of the reactive Si—H groups gives ALPHS an opportunity to further derive a variety of functional polymers by versatile Si—H reactions such as hydrosilylation,condensation,and so on.
A highly ordered m-phenylenediimino-bridged ladder polyhydrosiloxane (abbr. OLPHS) with Mn = 1.24 104 was synthesized under assistance of H-bonding template constructed from imino H-bonding, N(Si)-H N(Si)-H, via a modified process of stoichiometric hydrolysis and dehydrochlorination condensation reaction between Si–Cl and Si–OH bonds. The complete ladder structure of OLPHS has been confirmed by the following three data. Two characteristic Bragg’s peaks representing the ladder width (w =0:94 nm) and ladder thickness (t = 0.42 nm) were observed in XRD analysis, which are consistent with those cal- culated by molecular simulation. The very sharp absorption with a small half-peak width ew1=2=0:5 ppmT for [(–HN)HSiO2/2]n moiety of OLPHS in 29Si NMR spectrum indicated presence of the complete ladder structure. As collateral evidence, a higher glass transition temperature (Tg = 105 8C) is also recorded in the DSC measurement, implying the high stiffness of ladder chain of OLPHS.
Kui Lin DengTao Yi ZhangXiao Jing ZhangPing XieRong Ben Zhang
Surface enhanced Raman scattering (SERS) spectroscopy was first utilized to study the photo-orientation behaviour of the photoreactive groups on a novel photo-alignment film surface and elucidate the generation mechanism of pretilt angle. The novel photo-alignment film was prepared by spin-coating a solution of ladderlike polysiloxane (LPS) bearing dual photoreactive group on an ITO surface and by irradiation with linear-polarized ultraviolet (LPUV) light A Si—H terminal compound (M) containing an identical photosensitive part has been used to fabricate a model film for SERS investigation.
A novel soluble regular ladder poly(benzoyl-3-aminopropyl) silsesquioxane (LPBAS) was facilely prepared under effective assistance of concerted H-bonding self-assembly of amido groups of side chains and silanol groups, respectively, of a new template monomer [1,3-bis(benzoyl-3-aminopropyl)-1,1,3,3-tetraethoxydisiloxane] (M). The ordered ladder structure of LPBAS is manifested in: (1) the presence of two Bragg peaks representing the ladder width (d) and ladder thickness (t) in X-ray diffraction (XRD) pattern; (2) narrow base-line width (w = 6) of resonance absorption for -CH2SiO3/2 moiety in 29Si-NMR and (3) high glass transition temperature Tg = 112℃in differential scanning calorimetry (DSC) analysis.
