Thermal Transitions of the Alkali Palmitates

The Liquid Crystal Region in Cesium Soaps

“…6]. A fair agreement with the present results does occur only for the Fa value detected microscopically by Void and Void [3]. The overall trustworthiness and self-consistency of our DSC findings are supported: (i) by the similarity of the 515 aü F/S F ig.…”

“…DTA supplemented with microscopic observation [3], photometry [4], X-ray diffraction [5], and hot-stage polarizing microscopy [6], were employed by a number of investigators in order to identify the upper (Fa ; CI = clearing) and lower (Ff ; F = fusion) limits of the temperature intervals where even homologs with /?c = 12 (nc = number of carbon atoms) can exist as stable mesomorphic liquids. The results, however, have been far from satisfactory, inasmuch as differ ences of tens of degrees do occur both in the FC 1 and Ff values reported by different authors for a given homolog.…”

On the Thermal Behaviour of the n.C13 -n.C 20 Rubidium Soaps

“…3 on the basis of Table 2 and of previous results on RbCi-RbCi2 [9-111. Authors: GS, Gallot and Skoulios [1]; BDS, Baum, Demus and Sackmann [2]; VV, Void and Void [3]; BHP, Benton, Howe and Puddington [4]; SD, Shaw and Dunell [5]; RD, Ripmeester and Dunell [6]. SD and RD did not extend their observations up to the clear melt.…”

“…number of carbon atoms) is limited so far to an X-ray investigation by Gallot and Skoulios [1] on the even homologues up to nc = 22, a hot stage microscopic study by Baum, Demus and Sackmann [2] on tetra-, hexa-and octadecanoate, and a few more data obtained by other authors [3][4][5][6] with different techniques on either hexa-or octadecanoate. On the whole, the above works show that the room temperature cn^stalline form of each homologue turns to an isotropic liquid through a multiplicity of phase transitions, and that a region exists -immediately below the isotropic liquid -where a mesomorphic liquid crystalline phase is stable.…”

“…It is, however, to be noted that agreement is far from complete both for the total number of phases and for the extension of their fields of existence. Further, among the pertinent heat effects only those associated in rubidium hexadecanoate with fusion and with two lower transitions are available [3].…”