Journal article
Order and Dynamics Inside H-PDLC Nanodroplets: An ESR Spin Probe Study
The journal of physical chemistry. B, v 113(16), pp 5391-5402
23 Apr 2009
PMID: 19331398
Abstract
We have performed a detailed study of the order and dynamics of the commercially available BL038 liquid crystal (LC) inside nanosized (50-300 nm) droplets of a reflection-mode holographic-polymer dispersed liquid crystal (H-PDLC) device where. LC nanodroplet layers and polymer layers are alternately arranged, fort-ning a diffraction grating. We have determined the configuration of the LC local director and derived a model of the nanodroplet organization inside the layers. To achieve this, we have taken advantage of the high sensitivity of the ESR spin probe technique to study a series of temperatures ranging from the nematic to the isotropic phase of the LC. Using also additional information on the nanodroplet size and shape distribution provided by SEM images of the H-PDLC cross section, the observed director configuration has been modeled as a bidimensional distribution of elongated nanodroplets whose long axis is, on the average, parallel to the layers and whose internal director configuration is a uniaxial quasi-monodomain aligned along the nanodroplet long axis. Interestingly, at room temperature the molecules tend to keep their average orientation even when the layers are perpendicular to the magnetic field, suggesting that the molecular organization is dictated mainly by the confinement. This result might explain, at least in part, (i) the need for switching voltages significantly higher and (ii) the observed faster turn-off times in H-PDLCs compared to standard PDLC devices.
Metrics
Details
- Title
- Order and Dynamics Inside H-PDLC Nanodroplets: An ESR Spin Probe Study
- Creators
- Corrado Bacchiocchi - University of BolognaIsabella Miglioli - University of BolognaAlberto Arcioni - University of BolognaIlaria Vecchi - University of BolognaKashma Rai - University of BolognaAdam Fontecchio - University of BolognaClaudio Zannoni - University of Bologna
- Publication Details
- The journal of physical chemistry. B, v 113(16), pp 5391-5402
- Publisher
- American Chemical Society; Washington, DC
- Number of pages
- 12
- Grant note
- EU; European Commission MIUR; Ministry of Education, Universities and Research (MIUR) INSTM University of Bologna
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Electrical and Computer Engineering
- Web of Science ID
- WOS:000265269100008
- Scopus ID
- 2-s2.0-66349097225
- Other Identifier
- 991019168659504721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Chemistry, Physical