Multiple glassy dynamics in dipole functionalized triphenylene-based discotic liquid crystals revealed by broadband dielectric spectroscopy and advanced calorimetry – assessment of the molecular origin

Abstract

A selected series of dipole functionalized triphenylene-based discotic liquid crystals (DLCs) was synthesized and investigated in a systematic way to reveal the phase behavior and molecular dynamics.

Recent Advances in Nanoporous Anodic Alumina: Principles, Engineering, and Applications

“…To provide overview of many functionalities discussed in Sections 4.1-4.7, they are gathered in the Table 2. [190] Gradient-index filters [191] Distributed Bragg reflectors [192] Optical bandpass filters [193] Human protein heavy ions real-time interaction monitoring [194] Tailoring of optical properties with pulse anodization [149] Design of phase shift defect in effective refractive index [195] Hybrid distributed DBRs and apodized GIF photonic structure [196] Characterization of thermotropic ferroelectric liquid crystals confined in the NAA [197][198][199] Glass transition of discotic liquid crystals in one-dimensional fluid [200] Adjustable optical anisotropy by self-assembly of liquid crystals confined in porous structure [201] Sensors NAA template-assisted fabrication of chromium substrate for SERS detection of heavy ions in aqueous solutions [202] Au NPs array on NAA for SERS detection of hemoglobin [203] Controlled fabrication of periodic plasmonic dimer arrays for SERS [204] Graphene-NAA composite for SERS sensing [205] Label-free optical sensor based on interferometric reflectance spectroscopy for TNF-α detection [206] NAA-based interferometer for copper sensing [207] In vivo nanotubes nanotoxicity study on murine model […”

“…In recent experiments, the focus was directed on understanding a charge transport in such systems [200]. Discotic liquid crystals were investigated with regards to molecular dynamics and phase behavior.…”

Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry

“…24 After this first report about a glass transition in plastic crystals, glassy dynamics in plastic crystals are further reported and discussed in the literature. [25][26][27][28][29] Recently, the molecular mobility was studied for several CLC systems including HAT6 as well as HAT5 including dipole functionalized derivatives of the latter [30][31][32][33][34] . These investigations revealed a localized molecular mobility and multiple glassy dynamics detected in the Cry phase, which was also reported by other groups.…”

“…[17][18][19][20][21][22][23] For triphenylene-based DLCs, the detected glassy dynamics are attributed to cooperative fluctuations taking place in the columns and in the intercolumnar area. The faster glassy dynamics at lower temperatures (denoted as α2-relaxation [31][32][33] ) are assigned to rotational fluctuations of the disc-like core around the column axis coupled with parallel and perpendicular small scale motions of the triphenylene cores. The glassy dynamics taking place in the columns can be therefore referred as glass transition of a one-dimensional liquid.…”

“…The glassy dynamics taking place in the columns can be therefore referred as glass transition of a one-dimensional liquid. The slower glassy dynamics at higher temperatures (denoted as α1-relaxation [31][32][33] ) is assigned to the polyethylene-like (PE-like) fluctuations of the alkyl chains in the intercolumnar area coupled with a tumbling (tilt and twist motions) of the core.…”