Über die orientierte Aufwachsung von Polyäthylen auf Steinsalz

Perfectly Alternating Ethylene−Carbon Monoxide Copolymer Crystallized Epitaxially on Alkali Halides. 1. Morphological Observation by TEM

“…Figure a shows the typical rodlike morphology of POK crytallized epitaxially on the (001) face of NaCl from a nitrobenzene solution ( T c = 180 °C, t c = 5 min). This morphology is closely similar to those observed for polyethylene (PE) and polyoxymethylene (POM) crystals grown on various alkali halides. − ,− The two orthogonal sets of POK rodlike crystals are oriented at 45° to the shadowing direction (the arrow in Figure a), i.e . , parallel to the [110] and [1̄10] directions of the substrate.…”

“…In the present work, rodlike crystals of perfectly alternating ethylene−carbon monoxide copolymer (POK) have been successfully oriented on the (001) cleavage faces of the NaCl and KI single crystals by isothermal crystallization from a 0.01 wt % solution in nitrobenzene. The morphology, with a perpendicular orientation of the deposited rodlike crystals, bears close resemblance to that observed for PE and POM crystals grown on various alkali halides; that is to say, the rodlike crystals of PE and of POM are oriented in the 〈110〉 directions of the substrates. − ,− Though the orthorhombic PE grows favorably on KBr, the monoclinic form grows transiently just on NaCl, and the growth transition to the orthorhombic one occurs within a few nanometers from the NaCl surface. , As for POM, for example, the hexagonal form grows on KCl and NaCl, but the orthorhombic form is mingled with the hexagonal one on KI and KBr . The present TEM study on POK reveals the following: (i) Epitaxial interactions of POK with the NaCl (001) face are rather nonspecific in terms of crystalline phase as well as of contact plane.…”

Epitaxial crystallization of polyoxymethylene, polypropylene, and polypropylene oxide from solution on cleaved surfaces of alkali halides

“…It h a s been found recently that different homopolymers will grow epitaxially on freshly cleaved surfaces of alkali halides (1)(2)(3)(4)(5)(6)(7)(8). Usually "rod-like" crystallites grew from t h e substrate surfaces with their Iongest dimension predominantly aligned in t h e < 110 > directions of t h e (001) p l a n e s of t h e alkali halides.…”

Theory of the epitaxial crystallization of polymers on alkali halide substrates. III. Solvation effects

“…One can then define as being the number of force centers per unit length in the continuous distribution and is equal to the reciprocal of the fiber repeat for the chain. If dlj is a differential unit of length on line j, then Xdlj represents the number of force centers within dlj, and the dispersion, repulsive, and coulombic energy, d£y, between atom i and this line element, can be written as dEij = Xdlj Ay 1 Qj jdlj r¡j6\ try (3) where Ay and By are the dispersion and repulsive energy coefficients for the interaction between atom i and an atom in line j. r,j is the distance between dlj and i. Q¡ is the total partial charge of atom i and jy the charge per unit length of dl| Figure 3. Solvent atom / at a distance t>,y from (a) a collinear array, j, of discrete force centers in a rational helix having a fiber repeat of and, (b) a continuous distribution, j, of force centers having the same linear density as in (a).…”