Microfluidic flow assembly system with magnetic clamp for unlimited geometry in millimetric hydrogel film patterning

Foster, Daniel A. N.; Hwang, Dae Kun

doi:10.1016/j.apmt.2021.101330

Cited by 3 publications

(2 citation statements)

References 37 publications

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“…The methods were further described elsewhere. [41] Two-Step Synthesis of Motif-Encoded Hydrogel Film: Using a photomask, the hydrogel frame was synthesized using a prepolymer solution (95% (v/v) PEGDA (M n = 250), 5% (v/v) photo-initiator) at UV exposure of 1.00 s. The porogen solution (45% (v/v) PEGDA (M n = 250), 50% (v/v) ethanol, 5% (v/v) photo-initiator) was injected into the PDMS channel at 25 μL min −1 for ≈10 min to ensure the void features within the hydrogel film were filled with porogen solution. By using another photomask in the field-stop of the microscope, the motif feature was polymerized at UV exposure times of 3.00 s to induce the opacity change.…”

Section: Microfluidic Device Fabricationmentioning

confidence: 99%

Stimuli‐Responsive Optical Switching Patterns in Millimetric Hydrogel Frames: Nanomaterial‐Free Anti‐Counterfeiting Technology

Jegatheeswaran,

Hwang

2023

Adv Materials Technologies

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Stimuli‐responsive materials are employed in numerous on‐demand applications, such as anti‐counterfeiting. Although innovative hybrid spectral/graphical approaches have gained wide attention, they are limited by the need for user training and sophisticated technologies to decode the covert pattern which can be achieved through toxic organic dyes, pigments, up‐conversion crystals, nanoparticles, or self‐assembly of colloidal particles within a hydrogel framework. These approaches also involve a lengthy multistep fabrication that consumes several days. Although optical nanomaterials, which are responsive to external stimuli, such as magnetic field, can undergo a quicker self‐assembly, additional equipment is required to generate external fields and the use of nanomaterials alone limits this technology's wide applicability in consumer goods especially on food or pharmaceuticals. Here, a nanomaterial‐free technology is demonstrated that utilizes various microscale motifs to display an optical shifting behavior without the need for passive or active assembly of colloidal particles, and any toxic dyes, pigments, or nanomaterials. The optical shifting property is purely induced by hydrogel porous microstructures and resulting light scattering. The slit channel lithography technique makes it easy for users to authenticate products using a simple smartphone device or inverted microscope by validating the optical switching behaviors of motifs embedded in hydrogel frames.

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Section: Microfluidic Device Fabricationmentioning

confidence: 99%

Stimuli‐Responsive Optical Switching Patterns in Millimetric Hydrogel Frames: Nanomaterial‐Free Anti‐Counterfeiting Technology

Jegatheeswaran,

Hwang

2023

Adv Materials Technologies

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“…[26,28,29] In contrast, soft lithography techniques offer easier ways to fabricate micropatterned PhC materials. [30,31] For example, imprinting lithography, [32,33] micromolding-based evaporation-polymerization method, [34,35] microfluidic flow assembly system with magnetic clamp, [36] integration of hydrophilic PhCs by spraying method, [37] ultrafast self-assembly of microscale particles by open-channel flow [38] and templating methods [30,39,6] have been used to generate micropatterned opal and inverse opal structures; nevertheless, these methods often involve exquisitely controlled equipment or rely on mold with microwells to drive the patterning or assembly. [30,39] A possible solution to these challenges is a simple method based on an intermittent, "stick-slip" motion of the suspension meniscus during liquid evaporation [40] for deposition of micropatterned structures consisting from periodical array of narrow opaltype multilayer or monolayer stripes and empty blanks between them.…”

Section: Introductionmentioning

confidence: 99%

Fabrication Technique of Micropatterned Inverse Photonic Crystal Films

Ashurov,

Liu,

Ezhov

et al. 2023

Cryst. Res. Technol.

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A simple and frugal method for fabricating inverse micropatterned photonic crystal (PhC) films aimed at miniaturization and multiplexing of opaline PhCs is described. First, highly uniform micropatterned synthetic opal structures in the form of periodic stripes are formed via stick‐slip motion of the meniscus during SiO2 colloid solution evaporation. The prepared opal structures are then used as templates to produce inverse stripe patterned films with highly uniform colors via photopolymerization of ethoxylate trimethylolpropane triacrylate (ETPTA) photocurable resin. Local reflectance spectra are recorded to prove the PhC properties of the inverse stripes, and peaks over 40% associated with the first photonic stop band are observed. The readily fabrication process suggested here is an important step toward the development of many applications that can pave the technical road map for the next wave of innovations and breakthrough in PhCs for sensing. In particular, the resulting structures can be used as PhC arrays containing a line of periodically repeating sensor strips capable to detect the content of alcohols in water.

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Vacuum-driven assembly of electrostatically levitated microspheres on perforated surfaces

et al. 2022

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Microfluidic flow assembly system with magnetic clamp for unlimited geometry in millimetric hydrogel film patterning

Cited by 3 publications

References 37 publications

Stimuli‐Responsive Optical Switching Patterns in Millimetric Hydrogel Frames: Nanomaterial‐Free Anti‐Counterfeiting Technology

Stimuli‐Responsive Optical Switching Patterns in Millimetric Hydrogel Frames: Nanomaterial‐Free Anti‐Counterfeiting Technology

Fabrication Technique of Micropatterned Inverse Photonic Crystal Films

Vacuum-driven assembly of electrostatically levitated microspheres on perforated surfaces

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