Visible light initiated thiol-ene based reflection H-PDLCs

Lalgudi V. Natarajan; Dean P. Brown; Jeremy M. Wofford; Vincent P. Tondiglia; Richard L. Sutherland; Pam Lloyd; Rachel Jakubiak; Richard Vaia; Timothy J. Bunning

doi:10.1117/12.617376

22 August 2005 Visible light initiated thiol-ene based reflection H-PDLCs

Lalgudi V. Natarajan, Dean P. Brown, Jeremy M. Wofford, Vincent P. Tondiglia, Richard L. Sutherland, Pam Lloyd, Rachel Jakubiak, Richard Vaia, Timothy J. Bunning

Author Affiliations +

Proceedings Volume 5936, Liquid Crystals IX; 59360F (2005) https://doi.org/10.1117/12.617376
Event: Optics and Photonics 2005, 2005, San Diego, California, United States

Abstract

Multifunctional acrylate formulations containing nematic liquid crystals have been shown to form holographic polymer dispersed liquid crystal gratings (H-PDLCs) easily using ultra-violet AND/OR visible photoinitiators. Laser wavelengths of 364, 476, 488, 514, 532 and 647 nm have been used for the fabrication of the gratings. Recently, the use of a thiol-ene based monomer system has been shown to overcome some of the adverse effects like post polymerization, voltage creep, and non-uniform shrinkage incurred when using highly functional acrylate monomers. However, Bragg reflection gratings have only been demonstrated utilizing ultra-violet (UV) (363.8 nm Argon ion) photopolymerization. Using UV irradiation and single prism geometry limits the upper end of the reflection notch wavelength. In this work, we report on new visible photoinitiator systems developed for the formation of reflective H-PDLCs using thiol-ene monomers. Using these new photoinitiator systems, reflection notches have been routinely written from the visible to the near infrared (IR) regions. The visible photoinitiator systems included the photoinitiator and radical generator titanocene organo-metallic complex (commercially known as Irgacure 784 (Ciba-Geigy), Rhodamine 6G, Pyrromethene, and a radical generating organic peroxide as coinitiator. Reflection gratings were written using laser wavelengths 442, 488, and 532 nm with diffraction efficiencies (DEs) above 70%. Angle tuning allowed for gratings with reflection notches in the near IR (900-1500 nm) to be written using these initiator systems. Rhodamine 6G was found to be more efficient than the other two initiators. We discuss here this new chemistry, the morphology, and electro-optical properties of the reflection gratings.

Citation Download Citation

Lalgudi V. Natarajan, Dean P. Brown, Jeremy M. Wofford, Vincent P. Tondiglia, Richard L. Sutherland, Pam Lloyd, Rachel Jakubiak, Richard Vaia, and Timothy J. Bunning "Visible light initiated thiol-ene based reflection H-PDLCs", Proc. SPIE 5936, Liquid Crystals IX, 59360F (22 August 2005); https://doi.org/10.1117/12.617376

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available