A Novel Approach for the Creation of Electrically Controlled LC:PDMS Microstructures

Abstract

This work presents research on unique optofluidic systems in the form of air channels fabricated in PDMS and infiltrated with liquid crystalline material. The proposed LC:PDMS structures represent an innovative solution due to the use of microchannel electrodes filled with a liquid metal alloy. The latter allows for the easy and dynamic reconfiguration of the system and eliminates technological issues experienced by other research groups. The paper discusses the design, fabrication, and testing methods for tunable LC:PDMS structures. Particular emphasis was placed on determining their properties after applying an external electric field, depending on the geometrical parameters of the system. The conclusions of the performed investigations may contribute to the definition of guidelines for both LC:PDMS devices and a new class of potential sensing elements utilizing polymers and liquid crystals in their structures.

Periodic liquid crystalline waveguiding microstructures

“…Such a configuration allows for complex electrodes to be realized and placed in the close vicinity of the waveguiding channel. Considering the main topic of this work, it is worth noting that periodic waveguiding structures may be relatively easily achieved with use of electrodes of special design and geometry 31 .Specifically, a concept of fluid electrodes, allowing for periodic changes of refractive index along the liquid crystalline waveguide channel 31 , brought the idea of the possible application of LC:PDMS chips as the photonic Bragg-type structures.…”

“…We created LC:PDMS structures (see Fig. 2 ) using the typical cast-and-molding technique with the mold and waveguiding device fabrication processes described in our previous papers 31 – 33 , respectively. It must be underlined that all the samples presented in this work were obtained from high-quality molds fabricated using the photolithography process with UV illumination through the chrome mask 33 .…”

“…Following the fabrication procedures described in Refs. 31 – 33 , it was possible to obtain the channels with a height of about 30 µm (for the structures shown in Fig. 9 a–c) and 12 µm (for the structure shown in Fig.…”

Alignment and Actuation of Liquid Crystals via 3D Confinement and Two-Photon Laser Printing

“…It has been reported that the hydrophobic proper�es of PDMS surfaces induce a perpendicular anchoring effect of LC molecules (24,25). However, the fabrica�on of PDMS scaffolds has been limited to conven�onal molding method, using a PDMS-based master mold or microfluidics to manipulate LC orienta�ons (26,27), where the geometries and resolu�ons were very limited.…”

Formation of nano and micro scale hierarchical structures in MgO and ZnO quantum dots doped LC media: the role of competitive forces

“…These microstructures have novel biomedical applications, drug vehicles for pharmaceutical ingredients and in treatment of numerous diseases including cancers. Researchers have summarized the applications of mixture of E7 nematic LCs and polydimethylsiloxane (PDMS) polymeric material [26]. They created an electrically controlled liquid crystal and polymer microstructures and have suggested its potential sensing applications.…”