STUDY ON THE CLAY INTERLAMELLA REACTION FOR HIGHLY ORIENTATED MOLECULAR STRUCTURE

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Intercalation reaction has been extensively studied with a number of different approaches, experimentally as well as theoretically. Among inorganic materials, swelling clays were fairly profitable for understanding the interface characteristics between organic and inorganic materials, since the swelling clay as host allowed to confine various kinds of organic molecules as guest in its gallery. Numerical studies have been therefore focused on a well-orientated sequence of the functional organic molecules in the interlayrs of clay. On the other hand, the recent interests in Langmuir-Brodgett (LB) mono-and multilayr assemblies have originated from their potential use as ultrathin organic films with special and purposefully designed properties in microlithography, electro-optics, biochemical sensing, and tribology. For all these and other applications the careful control of the molecular structure and the microscopic order of the thin films-both lateral and traversal-are required.In this p … More aper we report on a new approach to fabricate the clay unit layrs/organic molecules multilayrs films using a conventional LB technique. It will be demonstrated that there is no other homogenized preparation techniques to from inorganic and organic composites in the nano-scale with a wide variety of possibilities for influencing ordered states and thus adjusting their properties. This is due to the fact that the organic ions or molecules are initially organized on a clay surface where the environmental parameters can be readily changed and in a wide range, comparing with the intercalation reaction.The surface pressure-area, pi-A isotherms were measured at 16ﾟC for the fabrication of the monolayrs of nanodeylamine on distillled water and aqueous solutions contained various quantities of hectorite clay (referred to as HT-C_<19>). By using the horizontal lifting method on the hydrophillic surface of glass substrate, the deposition of a suitable monolayr was observed. The extrapolated surface area per molecule was estimated to be 21-22A_2. Nine times this value (189A^2) was almost equivalent to 7 times the hexagonal block area, involving 6-member rings of SiO_4 tetrahedrons on the silica sheet (189.7 A^2). By assuming that a functional headgroup of nanodecylamine was ionized as +1, it was plausible that 9 molecules was sufficiently covered with the 7 mean-charges of clay sheets for keeping the electroneutrality.At lower quantity of clays, the monolayr of composites never be statified. This implied that the built-up of monolayrs was apparently conducted by the electrostatic interaction between cationic amine and anionic clay. In contrast, at larger quantity of clay, the condensation of LB film was observed on the water subphase as the deposition progressed. The observation implied that the collapse of monolayr or the crystallization of nanodecylamine itself occurred.According to the powder X-ray diffraction patterns of multilayr NaHT-C_<19> composites, the well-stratification of LB film was performed under a surface pressure of 20 to 35 dyn/cm at pH=5.80. The basal spacing of LB films was estimated to be 61-62 A,which corresponded to the bilayrs of alkylamines (Y-type).According to the chemical analysis and the consumed area of LB trough, the accumulative proportion in multilayred LB films was estimated. The accumulative proportion is scarcely changed between swelling clays, but steeply shifted from theoretical one with increasing the pH.The FTIR-RAS spectra of 15 layred hectorite-nanodecylamine films and nanodecylamine LB multilayred film demonstrated that the nu (CH_2) bands at 2917 and 2850 cm^<-1> are enhanced in intensity and width. These changes indicate conformational disordering of the-CH_2-chains with an accompanying transition dipole component perpendicular to the clay surface. A relative intensity changes of the delta (CH_2) band at 1467 cm^<-1> probably arises from the same origin.The temperature dependence of d_< (002) > peak intensity for montmorillonite-nanodecylamine indicated that Na^+-hectorite nanodecylamine and nanodecylamine LB films. On heating above 48ﾟC of melting temperature, nanodecylalkylamine LB film collapses. However, the geometrical arrangement of alkylamine molecules is changed stepwise in the composite LB film having the basal spacings of 61.5 A to 38.6 A,as being of an intercalated clay compound.Our results are explained by models which links particular chain orientations on the clay surface to the surface binding geometry of the terminal amine group and the lateral interlocking geometry of the zigzag hydrocarbon skeleton. Less