SynopsisA series of low-molecular-weight linear polyesters were epitaxially crystallized from dilute solution and the melt on a variety of organic and inorganic substrates. The rod-like polyester crystals which were formed assumed general orientations in alignment with substrate geometry. This yielded monodirectional orientation of these crystals on one of the organic substrates, and bidirectional orientation on the other surfaces. Heterogeneous nucleation on the organic substrates, trioxane and naphthalene, induced the growth of much larger epitaxial crystals than have previously been observed on inorganic substrates. Those polyesters, with a high percentage of methylene units per chain repeat, crystallized in an unusual polymorphic form when in contact with the organic substrates. Polymorphic transformation to the normal form was not possible under thermal treatment or with increased crystal thickness. The expected relationship between dipolar alignment in the polymer crystal and this polymorphism was established. samples or under thermal treatment. Similarly, solution crystallization of isotactic polypropylene on alkali halides near the bulk melting point, allowed the formation of the unusual triclinic form.g
Epitaxial growth of synthetic polymers on alkali-halide surfaces usually proceeds along the preferred 〈110〉 directions parallel to the {100} plane of the substrate. Polyoxymethylene was epitaxially crystallized as thin films on alkali halides and analyzed using the electron microscope. The metastable orthorhombic crystal form was obtained on substrates which exhibited a lattice match with the [100] distance of the orthorhombic form. Matching was not necessary for the growth of the normal hexagonal crystal form, although it did affect both the nucleation process and the growth rate of the epitaxial crystallization. The technique seems to be quite generally applicale in affecting the general morphology of the crystallization and the formation of metastable polymeric forms.
Ohio 44106 synopsis Poly(bismethy1ene hydroquinone) (PBHQ) has been synthesized. Fourier transform infrared, l3C solid-state -/MAS NMR and elemental analysis provide strong evidence of two methylene ( A H , \ ) bridgea per hydroquinone molecule. The polymer waa (1) air oxidized using ammonia and (2) chemically oxidized using bromine/KOH. The initial structure and oxidation process was studied by comparison of the unoxidized and oxidized polymers using Fourier transform infrared, elemental analysis, and '3c solid-state CP/MAS NMR. 2660 DALAL, LITI', AND RICKERT The Andrew-Beam type spinners were constructed from polyoxymethylene (Delrin), and were spun with a speed in the range of 3.5 KHz. The resolution of Delrin (89 ppm) was used as a reference.The elemental analysis on dried samples were done by the Galbraith Laboratories, Knoxville, TN. Synthesis of Poly(bismethy1ene Hydroquinone) (PBHQ)5.5 g (0.061 moll of trioxane and 10.0 g m s (0.091 moll of hydroquinone were placed in a pressure vessel. 0.1 gm of toluene sulphonic acid, 70 cc of sulfolane and 30 cc of distilled water were added. The pressure vessel was closed; vacuum was applied for 5 min and the vessel was sealed under vacuum. The reaction was carried out at 175°C for 1 h in a silicone oil bath. The pressure vessel was cooled overnight, the product was removed and boiled for 15 min with 1000 cc of water three times to remove sulfolane. The product was filtered and dried in a vacuum oven for 24 h at 120°C. 11.5 gms of black product was obtained. The dried product was characterized by Fourier transform infrared, '3c solid-state CP/MAS NMR, and elemental analysis.
This paper describes the synthesis of the novel amphiphilic two-ring phthalocyanine (HO)GePcO-SiPc(OSi(n-C6H13)3) (where Pc is the phthalocyaninato dianion), the formation of a monolayer of this compound in which the rings are parallel to the plane of the monolayer, and some properties of this monolayer. The paper also describes the preparation by the Langmuir-Blodgett technique of multilayers of the compound in which the rings appear to be parallel to the substrate plane and the fabrication and properties of metal-insulator^metal devices constructed of aluminum electrodes and films of the compound of varying thicknesses. It is shown that the phase-change pressure of the monolayer is 17 mN/m and thus is sufficiently high to facilitate its deposition on a solid substrate. It is estimated that the relative permittivity of the multilayers is 5.5 ± 0.2 and thus is consistent with the permittivities reported for multilayers of porphyrins. The monolayer and multilayers are representatives of a new class of dielectric films. They are almost certainly highly anisotropic and have the potential to be used in a molecular engineering capability as components for complex microelectronic devices. edged.Registry No. (HO)GePcOSiPc(OSi(n-C6H13)3), 115461-96-6.
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