Journal article
The influence of N-vinyl-2-pyrrolidinone in polymerization of holographic polymer dispersed liquid crystals (HPDLCs)
Polymer (Guilford), Vol.47(7), pp.2289-2298
03/22/2006
DOI: 10.1016/j.polymer.2006.01.030
Abstract
Holographic polymer dispersed liquid crystals (HPDLCs) are targeted for application in a wide range of devices as dynamically switchable transmission or reflection diffraction gratings tunable through the visible spectra. The inclusion of N-vinyl pyrrolidinone (NVP) has been shown to reduce liquid crystal (LC) droplet size in HPDLC gratings and subsequently improve HPDLC performance. In this work, the influence of NVP on HPDLC polymer/LC morphology is examined and correlated to the influence of NVP on HPDLC photopolymerization kinetics and LC phase separation. As in other photopolymer systems, NVP significantly increases the rate of polymerization in HPDLC photopolymerization. In all the HPDLC formulations studied, NVP is completely incorporated into the polymer network while less than half of acrylate double bonds react. Furthermore, as the highly cross-linked polymer network forms, the small mono-vinyl NVP appears to react preferentially with acrylate double bonds, facilitating additional conversion of pendant double bonds otherwise trapped in the polymer network. NVP also induces a delay in the onset of reaction diffusion termination and extends the range of conversions for which reaction diffusion is observed. Interestingly, NVP also impacts polymer/LC morphology by delaying LC phase separation to higher double bond conversions. Together, the influence of NVP on the polymerization kinetics and LC phase separation alters HPDLC morphology by limiting LC droplet size, consequently resulting in improved HPDLC performance.
Details
- Title: Subtitle
- The influence of N-vinyl-2-pyrrolidinone in polymerization of holographic polymer dispersed liquid crystals (HPDLCs)
- Creators
- Timothy J White - Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242-1547, USAWilliam B Liechty - Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242-1547, USALalgudi V Natarajan - Science Applications International Corporation (SAIC), Dayton, OH 45433, USAVincent P Tondiglia - Science Applications International Corporation (SAIC), Dayton, OH 45433, USATimothy J Bunning - Air Force Research Labarotory (AFRL), Materials and Manufacturing Directorate, Wright Patterson Air Force Base, OH 45433, USAC. Allan Guymon - Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242-1547, USA
- Resource Type
- Journal article
- Publication Details
- Polymer (Guilford), Vol.47(7), pp.2289-2298
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.polymer.2006.01.030
- ISSN
- 0032-3861
- eISSN
- 1873-2291
- Language
- English
- Date published
- 03/22/2006
- Academic Unit
- Chemical and Biochemical Engineering
- Record Identifier
- 9984003474202771
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