Molecular Order of the Mesogens in Smectic Poly(ester imide) Fibers

Abstract

The molecular order of the mesogens in the smectic liquid-crystalline (LC) and smectic-crystalline phases of different poly(ester imide)s (PEI) with similar chemical structure is investigated by means of X-ray fiber patterns. During the fiber spinning from the melt, the smectic LC phase is frozen. Above the glass transition temperature, a transition into a higher-ordered smectic-crystalline phase occurs. The PEI which are based on aminobenzoic acid trimellitimide and long aliphatic spacers form exclusively orthogonal smectic phases (SA, SB, SE). In contrast, the PEI based on aminocinnamic acid trimellitimide and those derived from 4-hydroxyphthalic acid, aminophenol, and aliphatic dicarbon acids form tilted SC phases. The layer line broadening of the X-ray reflections indicates a poor lateral order of the smectic layers in the LC phase due to a frequent inversion of the staggering direction between adjacent mesogens. As a result of the equatorial smearing of the four-point-pattern, the splitting angle of the reflections is not identical with the tilt angle between the mesogens and the normal of the smectic layer plane. The order of the mesogens in the direction perpendicular to the fiber axis is evaluated on the basis of the paracrystallinity model. The resulting local tilt angle corresponds to an average staggering amount of the mesogens. Furthermore, the parameter ε, introduced by Porod, is interpreted as a probability for the inversion of the staggering direction.

Self-Repair of a Biological Fiber Guided by an Ordered Elastic Framework

“…Previous studies have suggested that preCols may be stored as a smectic liquid crystal phase in secretory vesicles prior to secretion , and that this “pre-ordering” may contribute to the rapid self-assembly. In fact, the SAXS patterns observed in our study are clearly reminiscent of those observed for certain smectic liquid crystalline fibers, which offers support to this hypothesis. The primary results of this study support the importance of structural order on mechanical behavior and self-repair.…”

Reversible actuating and writing behaviours of a head-to-side connected main-chain photochromic liquid crystalline polymer

“…This explanation can be supported by the fact that the cybotactic SmC uctuation clusters have been oen observed in the laterally attached sidechain LC polymers. [58][59][60][61][62][63][64][65][66] Reversible photo-actuating behaviours of the uniaxially oriented microbre…”

Phase Transition and Transition Kinetics of a Thermotropic Poly(amide−imide) Derived from 70 Pyromellitic Dianhydride, 30 Terephthaloyl Chloride, and 1,3-Bis[4-(4‘-aminophenoxy)cumyl]benzene

“…11 Interestingly, quite a number of liquid crystalline poly-(ester-imide)s derived from this ester-imide group exhibit layered smectic structures. [12][13][14][15] In a later attempt to synthesize liquid crystalline polyimide from PMDA, it was found that the combination of PMDA with a ester-free diamine, 1,3-bis[4-(4′-aminophenoxy)cumyl]benzene (BACB), which is also nonmesogenic, could form a stable smectic phase upon melting. [16][17][18][19][20] However, like other PMDA-based aromatic polyimides, this liquid crystalline polyimide, PMDA-BACB, shows very poor solubility in common organic solvents.…”

“…On the contrary, the asymmetric ester−imide group, N -[4-(chloroformyl)phenyl]-4-(chloroformyl) phthalimide, has demonstrated to be a good mesogenic unit which could form mesophases through reactions with a variety of diols, − although the homopolymer, poly[4-(hydroxyphenyl)trimellitic acid imide], did not exhibit liquid crystallinity due to its high melting temperature − In a later attempt to synthesize liquid crystalline polyimide from PMDA, it was found that the combination of PMDA with a ester-free diamine, 1,3-bis[4-(4‘-aminophenoxy)cumyl]benzene (BACB), which is also nonmesogenic, could form a stable smectic phase upon melting. − However, like other PMDA-based aromatic polyimides, this liquid crystalline polyimide, PMDA−BACB, shows very poor solubility in common organic solvents. On the other hand, the reaction of BACB with terephthaloyl chloride (TPC) can produce a polyamide, which is soluble in N -methyl-2-pyrrolidone (NMP) at room temperature.…”