Study of PDMS Microchannels for Liquid Crystalline Optofluidic Devices in Waveguiding Photonic Systems

Baczyński, Szymon; Sobotka, Piotr; Marchlewicz, Kasper; Juchniewicz, Marcin; Dybko, Artur; Rutkowska, Katarzyna A.

doi:10.3390/cryst12050729

Cited by 4 publications

(5 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Stress can concentrate at defects such as small nicks, thickness inhomogeneities, and imperfections associated with the fabrication process. 60,61 Consequently, the standard deviations of the force required to fail for both modes overlap in this transition region. Figure 2 reports the force at failure, but this value depends on the geometry of the sample.…”

Section: Resultsmentioning

confidence: 94%

See 1 more Smart Citation

Flexible-to-Stretchable Mechanical and Electrical Interconnects

Erlenbach

Mondal

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Stretchable electronic devices that maintain electrical function when subjected to stress or strain are useful for enabling new applications for electronics, such as wearable devices, human−machine interfaces, and components for soft robotics. Powering and communicating with these devices is a challenge. NFC (near-field communication) coils solve this challenge but only work efficiently when they are in close proximity to the device. Alternatively, electrical signals and power can arrive via physical connections between the stretchable device and an external source, such as a battery. The ability to create a robust physical and electrical connection between mechanically disparate components may enable new types of hybrid devices in which at least a portion is stretchable or deformable, such as hinges. This paper presents a simple method to make mechanical and electrical connections between elastomeric conductors and flexible (or rigid) conductors. The adhesion at the interface between these disparate materials arises from surface chemistry that forms strong covalent bonds. The utilization of liquid metals as the conductor provides stretchable interconnects between stretchable and non-stretchable electrical traces. The liquid metal can be printed or injected into vias to create interconnects. We characterized the mechanical and electrical properties of these hybrid devices to demonstrate the concept and identify geometric design criteria to maximize mechanical strength. The work here provides a simple and general strategy for creating mechanical and electrical connections that may find use in a variety of stretchable and soft electronic devices.

show abstract

Section: Resultsmentioning

confidence: 94%

“…This range is likely due to the sensitivity of catastrophic failure to defects. Stress can concentrate at defects such as small nicks, thickness inhomogeneities, and imperfections associated with the fabrication process. , Consequently, the standard deviations of the force required to fail for both modes overlap in this transition region.…”

Section: Resultsmentioning

confidence: 99%

Flexible-to-Stretchable Mechanical and Electrical Interconnects

Erlenbach

Mondal

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…The resultant alignment of NLC molecules within PDMS-embedded microchannels strongly depends on the channels' aspect ratio 58 , the quality of the molds used in the fabrication process 33 , and the method of connecting the PDMS chip to a substrate 59 . Based on previous studies 32 , 33 , 60 , 61 , it has been concluded that the best results in terms of predictability, reproducibility, robustness, and stability of LC molecular alignment in LC:PDMS structures are obtained for the molds obtained in the photolithography process 33 and with the assistance of the plasma treatment, reducing the PDMS surface roughness 60 , 61 . In fact, such procedures have been applied when fabricating the samples shown in this paper.…”

Section: Resultsmentioning

confidence: 98%

“…9 d), respectively. A detailed description enriched with the photos taken with Hitachi SU-8230 SEM to verify the quality of the structures in the PDMS is presented in our previous publication 32 . The roughness of the sidewalls of the PDMS channels fabricated using the SU-8 mold was negligible (< 400 nm).…”

Section: Methodsmentioning

confidence: 99%

Periodic liquid crystalline waveguiding microstructures

Ertman,

Orzechowski,

Rutkowska

et al. 2023

Sci Rep

View full text Add to dashboard Cite

Different methods allowing for creating optical waveguides with liquid–crystal (LC) cores, in which molecules form periodic patterns with precisely controlled periods, are reported. The first one is based on reversible photoalignment with high-resolution selective illumination and allows to control the period of LC molecules inside silica microcapillaries. The second method employs microstructures formed in PDMS, allowing to obtain both: LC-core waveguides and a set of specially designed periodic microelectrodes used for the periodic reorientation of molecules. Using both methods, we successfully controlled the period of the patterned alignment in the range from about 500 µm and scaled it down to as small as 20 µm. We performed experimental studies on waveguiding phenomenon in such structures, in view to obtain transmission spectra typical to optical fiber gratings. Since the results achieved in experimental conditions differed from those expected, the additional numerical simulations were performed to explain the observed effects. Finally, we obtained the waveguiding in a blue phase LC, characterized by naturally created three-dimensional periodicity with periods smaller than one micrometer. In such a structure, we were able to observe first-order bandgap, and moreover, we were able to tune it thermally in nearly the whole visible spectral range.

show abstract

“…As a first step, PDMS 3D microscaffolds were fabricated via 2PLP (see Figure S1 in the Suppor�ng Informa�on), which offers several advantages compared to the conven�onal micro-replica molding methods. 2PLP enables not only the construc�on of mul�ple 3D scaffolds with varied geometries in a single print, but also avoids rough surfaces and ar�facts which are typically observed when using molding methods, causing undesirable topological defects (24,28,29). For this purpose, a commercially available PDMS-based ink (IP-PDMS, Nanoscribe GmbH) was employed (30).…”

Section: Fabrica�on Of Pdms-based 3d Microscaffolds and Lc Alignmentmentioning

confidence: 99%

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

Hsu,

Gomez Melo,

Vazquez-Martel

et al. 2024

Preprint

View full text Add to dashboard Cite

Liquid crystalline (LC) materials are especially suited for the preparation of active 3D/4D microstructures using two-photon laser printing. To achieve the desired actuation, the alignment of the LCs must be controlled during the printing process. In most cases studied to date, the alignment relied on surface modifications and therefore, complex alignment patterns and concomitant actuation were not possible. Here, we introduce a strategy for spatially aligning LC domains in three-dimensional space by utilizing 3D-printed polydimethylsiloxane-based microscaffolds as confinement barriers, which induce the desired director field. The director field resulting from the boundary conditions is calculated with Landau de Gennes theory and validated by comparing experimentally measured and theoretically predicted birefringence patterns. We demonstrate our procedures for structures of varying complexity and then employed to fabricate 4D microstructures that show the desired actuation. Overall, we obtain excellent agreement between theory and experiment. This opens the door for rational design of functional materials for 4D (micro)printing in the future.

show abstract

Study of PDMS Microchannels for Liquid Crystalline Optofluidic Devices in Waveguiding Photonic Systems

Cited by 4 publications

References 41 publications

Flexible-to-Stretchable Mechanical and Electrical Interconnects

Flexible-to-Stretchable Mechanical and Electrical Interconnects

Periodic liquid crystalline waveguiding microstructures

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

Contact Info

Product

Resources

About