Holographically Formed Polymer Dispersed Liquid Crystals

What is an H-PDLC?

A typical HPDLC sample.  The insets show the liquid crystal droplets layered between polymer.  The sample on the left has voltage applied so all wavelengths of light are transmitted.  On the right, no voltage is applied so the Bragg wavelength is reflected, in this case green.

A typical HPDLC sample.  The insets show the liquid crystal droplets layered between polymer.  The sample on the left has voltage applied so all wavelengths of light are transmitted.  On the right, no voltage is applied so the Bragg wavelength is reflected, in this case green.

Holographic polymer-dispersed liquid crystals (HPDLCs) are a class of materials with unique electro-optical properties.  HPDLCs are formed by exposing a mixture of liquid crystals, monomers, and photoinitiator to a standing wave creating by the interference of multiple laser beams.  The monomers polymerize in the bright regions and push the liquid crystals into the dark regions.  This creates a Bragg grating of liquid crystal and polymer.  The grating reflects only one specific wavelength of light and transmits all the others.  The particular wavelength that is reflected is a function of the refractive index difference and the width of the layers in the grating.  When a voltage is applied the liquid crystals align with the field and their new refractive index matches that of the polymer, causing the grating to become transparent.

A scanning electron microscope image of an HPDLC.

A scanning electron microscope image of an HPDLC.

Why Study H-PDLCs?

Current displays using liquid crystal technology are designed in such a way that a backlight is required (think of the light that comes from your computer monitor or TV).  This light feeds on a huge portion of battery life, and so is inconvenient in situations that require long-lasting devices.

Kindles and other e-readers use technology that allows for ambient light to be reflected from their displays.  This is done through e-ink, in which white and black charged particles float to the top or the bottom of the display depending on the electric field.  This technology has the limitation that the "switching time" (the time it takes to turn the page) is too long to be of use in fast display requirements such as video.

Therefore, the H-PDLC technology can be developed to create a reflective, low-battery display that takes advantage of ambient light but maintains fast switching capability.  In addition H-PDLCs have great potential in creating fiber optic signal filtration and control, inexpensive spectrometers, dynamically reconfigurable contact photolithography masking layers, and optically switchable mirrors.

Related Publications

 

S. K. Shriyan, E. Schundler, C. Schwarze and A. K. Fontecchio, "Electro optic polymer-liquid crystal thin films for hyperspectral imaging", Journal of Applied Remote Sensing, accepted May 2011

S. K. Shriyan and A. K. Fontecchio, "Analysis of effects of oxidized multiwalled carbon nanotubes on electro-optic polymer/liquid crystal thin films'" Optics Express, 18, 2484224852 (2010)

S. K. Shriyan and A. K. Fontecchio, "Holographic electro-optic thin film stacks for airborne hyperspectral imaging," Proceedings of SPIE, 7812, 78120S (2010).

S. K. Shriyan, C.W. Hicks IV and A. K. Fontecchio, "Modification in diffusion kinetics and electro optic behavior of holographic thin films in presence of carbon nanotubes", Proceedings of SPIE, Vol. 7750, 77501G (2010)

S. K. Shriyan and A. K. Fontecchio, Improved electro-optic response of polymer dispersed liquid crystals dopes with oxidized multiwalled carbon nanotubes, Molecular Crystals and Liquid Crystals, Volume 525, January 2010 , pages 158 - 166

S. K. Shriyan, C. William Hicks IV, and Adam K. Fontecchio, "Modification in diffusion kinetics and electro-optic behavior of holographic thin films with carbon nanotubes" Proc. SPIE 7750, 77501G (2010), DOI:10.1117/12.871816

S. K. Shriyan and A. K. Fontecchio, "Holographic electro-optic thin film stacks for airborne hyperspectral imaging" Proc. SPIE 7812, 78120S (2010), DOI:10.1117/12.860727

S. K. Shriyan and A, K. Fontecchio, Electro-optical effects of oxidized multiwalled carbon nanotube doping on holographic polymer dispersed liquid crystal films, Proceedings of SPIE, 7414, 741407 (2009)

C. Bacchiocchi, I. Miglioli, A. Arcioni, I. Vecchi, K. Rai, A. Fontecchio and C. Zannoni, "Order and dynamics inside h-pdlc nanodroplets: An esr spin probe study", Journal of Physical Chemistry B, vol.113, no.16, pp. 5391-5402, Apr 2009.

K. Rai, S. K. Shriyan and A. K Fontecchio, "Variable Pressure and Environmental SEM of Thin-Film Liquid Crystal/Polymer Composites," Microscopy and Microanalysis, 23,17 (2009)

C. Bacchiocchi, I. Miglioli, A. Arcioni, I. Vecchi, K. Rai, A. Fontecchio and C. Zannoni, "Order and Dynamics Inside H-PDLC nanodroplets: an ES

A.E. Fox and A.K. Fontecchio, Applications of liquid crystal polymer composite films for photolithographic fabrication of 3D structures", Proceedings of the SPIE Symposium on Integrated Optoelectronic Devices, Practical Holography XXII: Materials and Applications, Vol. 6912 (2008).

S. Shriyan, K.Rai, A.A. Bellingham, and A.K. Fontecchio, "Multilayer stacking technique for holographic polymer dispersed liquid crystals". Applied Physics Letters 93, 261113(2008)

A.E. Fox and A.K. Fontecchio, \Applications of liquid crystal polymer composite films for photolithographic fabrication of 3D structures", Proceedings of the SPIE Symposium on Integrated Optoelectronic Devices, Practical Holography XXII: Materials and Applications, Vol. 6912 (2008). 

A.E. Fox, K. Rai., A.K. Fontecchio, \Holographically Formed Polymer Dispersed Liquid Crystal Films for Transmission Mode Spectrometer Applications", Applied Optics, 46 (27) 6277 { 6282 (2007).

A.E. Fox, M. Cosgrove-Davies, A.K. Fontecchio, \Gap Material Study for Holographically Formed Polymer Dispersed Liquid Crystal Composite Film Stacks", Molecular Crystals Liquid Crystals, Vol. 478, 151-162 (2007)

M. Ermold and A. K. Fontecchio, \Electrically Switchable Holographic Parabolic Mirrors,"Journal of Applied Physics, 99 093111 (2006).

H. J. Shah and A. K. Fontecchio, \Low-Voltage Color Switching in Liquid Crystal Displays", IDRC 2006 Digest Society for Information Display, P-27 ( 2006).

M. L. Ermold, A. K. Fontecchio, \Viewing angle enhancement in holographic reflective displays by nanoscale holographic patterning,"Journal of the Society of Information Displays 13, 787 (2005). (WOS Citations = 2, GS Citations = 1)

M. Ermold, K. Rai, A. K. Fontecchio, \Hydrostatic pressure response of polymer-dispersed liquid crystal gratings,"Journal of Applied Physics, 97, 104905 (2005). (WOS Citations = 1)

H. J. Shah and A.K. Fontecchio, \Image analysis to study LC alignment on nanopatterned substrates", Molecular Crystals and Liquid Crystals, 438, 1855 { 1866 (2005).

I. Drevensek-Olenik, M. Jazbinsek, M. Sousa, A. K. Fontecchio, G. P. Crawford, and M. Copic, \Structural Transitions in Holographic Polymer Dispersed Liquid Crystals," Physical Review E, 69, 051703 (2004). (WOS Citations = 8, GS Citations = 2)

M. L. Ermold and A. K. Fontecchio, \Optical Response of Reflection Polymer Bragg Gratings to Applied Gas Pressure," Proceedings of the SPIE, 5518, 115-118, (2004).

H. J. Shah and A. K. Fontecchio, \Modeling and Experimental Study of LC Alignment Induced by Nanopatterned Substrates," Proceedings of the SPIE, 5518, 144-147, (2004).

A. K. Fontecchio and H. J. Shah, \Nanopatterned Polymer Structured for H-PDLCs,"in Physical Chemistry of Interfaces and Nanomaterials II, Tianquan Lian and Hai-Lung Dai, Editors, Proceedings of the SPIE, 5223, (2003).

J. Qi, M. E. Sousa, A. K. Fontecchio, and G. P. Crawford, \Temporally Multiplexed Holographic Polymer-Dispersed Liquid Crystals," Applied Physics Letters,82, 1652-1654 (2003). (WOS Citations = 20, GS Citations = 14)

M. Vilfan, B. Zalar, A. K. Fontecchio, M. Vilfan, M. J. Escuti, G. P. Crawford, and S.Zumer, \Deuteron NMR Study of Molecular Ordering in a Holographic Polymer Dispersed Liquid Crystal", Physical Review E, 66, 021710 (2002). (WOS Citations = 10, GS Citations= 8)

M. Jazbinsek, I. Drevensek-Olenik, M. Zgonik, A. K. Fontecchio, and G. P. Crawford, \Electro-Optical Properties of Polymer Dispersed Liquid Crystal Transmission Gratings", Molecular Crystals and Liquid Crystals, 375,455 - 465 (2002). (WOS Citations = 9, GS Citations = 5)

A. K. Fontecchio, G. P. Crawford, and D. Content, \Cavity Morphology of Polymer Dispersed System Utilizing Atomic Force Microscopy," MRS Symposium Proceedings, 79, CC6.5.1 - CC6.5.6 (2002).

A. K. Fontecchio, G. P. Crawford, et. al., \Performance Improvements for Switchable H-PDLC Gratings Using Morphological Studies," in Solar and Switching Materials, Proceedings of the SPIE, 4458, 230 { 239 (2001).

A. K. Fontecchio, J. Qi, M. J. Escuti, I. Amimori, G. P. Crawford, and S. Faris, Diffuse Renditions of Spatially Pixelated and Temporally Multiplexed H-PDLCs for Full Color Reflective Displays," SID Digest of Technical Papers XXXII, 31,348 { 351 (2001). (WOS Citations = 2)

A. K. Fontecchio, C. C. Bowley, S. M. Chmura, Le Li, S. Faris, and G. P. Crawford, Multiplexed Holographic Polymer Dispersed Liquid Crystal Gratings," Journal of Optical Technology, 68 (9) 652-656 (2001). Selected Best Paper from ASID 2000. (WOS Citations = 5)

M. Jazbinsek, I. Drevensek-Olenik, M. Zgonik, A. K. Fontecchio, and G. P. Crawford, Characterization of Holographic Polymer Dispersed Liquid Crystal Transmission Gratings," Journal of Applied Physics, 90(8) 3831 { 3837 (2001). (WOS Citations = 34, GS Citations= 29)

D. P. Cairns, C. C. Bowley, S. Danworaphong, A. K. Fontecchio, G. P. Crawford, L. Li, and S. Faris, \Optical Strain Characteristics of Holographically Formed Polymer-Dispersed Liquid Crystal Films," Applied Physics Letters, 77 (17), 2677 { 2679 (2000). (WOS Citations= 20)

C. C. Bowley, A. K. Fontecchio, et. al., \Multiple gratings simultaneously formed in holographic polymer-dispersed liquid-crystal displays,"Applied Physics Letters, 76 (5), 523 {525 (2000). (WOS Citations = 25, GS Citations = 20)

A. K. Fontecchio, C. C. Bowley, et. al.,, Effect of Monomer Functionality on Performance of Holographically-formed Polymer Dispersed Liquid Crystals," Molecular Crystals and Liquid Crystals, 352, 399 { 406, (2000). (WOS Citations = 4, GS Citations = 3)

A. K. Fontecchio, C. C. Bowley, S. M. Chmura, Le Li, S. Faris, and G. P. Crawford, Multiplexed Holographic Polymer Dispersed Liquid Crystal Gratings," ASID 00 Proceedings The Sixth Asian Symposium on Information Display & Exhibition, 6, 116 { 121, (2000).

A. K. Fontecchio, M. J. Escuti, et. al., \Spatially Pixelated Reective Arrays from Holographic-Polymer Dispersed Liquid Crystals," SID Digest of Technical Papers XXXI, 31 (2000). (WOS Citations = 9, GS Citations = 2)

A. K. Fontecchio, C. C. Bowley, et. al., \Improvement in Holographically{formed Polymer Dispersed Liquid Crystal Performance through Acrylated Monomer functionality Studies," in Liquid Crystals III, Iam-Choo Khoo, Editor, Proceedings of the SPIE, Vol. 3800, pp. 36-44 (1999). (WOS Citations = 11, GS Citations = 13)

C. C. Bowley, A. K. Fontecchio, et. al., \Electro-Optic Investigations of H-PDLCs: The Effect of Monomer Functionality on Display Performance," SID Digest of Technical Papers XXX, 30 (1999). (GS Citations = 12)

C. C. Bowley, A. K. Fontecchio, et. al., \Advances in Holographic Polymer Dispersed Liquid Crystal Technology," MRS Symposium Proceedings, 559, pp.97 108 (1999). (GS Citations = 12)