905434-58-4Relevant academic research and scientific papers
Achiral bent-core molecules with a series of linear or branched carbosilane termini: Dark conglomerate phases, supramolecular chirality and macroscopic polar order
Zhang, Yongqiang,Baumeister, Ute,Tschierske, Carsten,O'Callaghan, Michael J.,Walker, Christopher
, p. 2869 - 2884 (2011/11/14)
New organic-inorganic hybrid materials that combine a bent π-conjugated aromatic core with one linear or branched carbosilane unit have been synthesized and investigated, with respect to their self-assembly in liquid crystalline (LC) phases, by means of polarizing microscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and electro-optical techniques. Most of these achiral compounds show spontaneous symmetry breaking into chiral superstructures that represent conglomerates with macroscopic domains of opposite handedness. These fluid chiral superstructures can be frozen into the glassy state and, for one of the compounds, chirality was switched under the application of a special waveform of an applied external electric field between two enantiomeric states. This flipping of supramolecular chirality occurs between oppositely tilted structures, which represents a new mode of chirality switching. Besides spontaneous chirality, these materials show polar order, leading to ferroelectric (FE) and antiferroelectric (AF) switching modes. For one compound with a highly branched carbosilane unit, a temperature-, voltage-, and frequency-dependent reversible transition from AF switching with inversion of chirality to FE switching with retention of chirality was observed. Models were developed to explain the experimental observations, based on enthalpic and entropic contributions of distinct supermolecular arrangements in these soft matter systems.
Silicon-containing polyphilic bent-core molecules: The importance of nanosegregation for the development of chirality and polar order in liquid crystalline phases formed by Achiral molecules
Keith, Christina,Reddy, R. Amaranatha,Hauser, Anton,Baumeister, Ute,Tschierske, Carsten
, p. 3051 - 3066 (2007/10/03)
Polyphilic molecules composed of a bent aromatic core, oligo(siloxane) units, and alkyl segments were synthesized, and the self-organization of these molecules was investigated. Most materials organize into polar smectic liquid crystalline phases. The swi
End functionalised liquid crystalline bent-core molecules and first DAB derived dendrimers with banana shaped mesogenic units
Kardas, Dorota,Prehm, Marko,Baumeister, Ute,Pociecha, Damian,Amaranatha Reddy,Mehl, Georg H.,Tschierske, Carsten
, p. 1722 - 1733 (2007/10/03)
New series of non-symmetric bent-core compounds with a terminal carboxylic function as well as its benzyl esters and pentafluorophenyl esters have been synthesised. For most pentafluorophenylesters and for a benzylester with fluorine atoms in the ortho po
Chirality and macroscopic polar order in a ferroelectric smectic liquid-crystalline phase formed by achiral polyphilic bent-core molecules
Dantlgraber, Gert,Eremin, Alexei,Diele, Siegmar,Hauser, Anton,Kresse, Horst,Pelzl, Gerhard,Tschierske, Carsten
, p. 2408 - 2412 (2007/10/03)
In conventional fluids the molecular dipole moments of the individual molecules cancel out, which leads to a macroscopic apolar structure. Directed molecular design using microsegregation and tailoring the molecular shape of compounds such as 1, can lead
