Ferrofluid-molding method for polymeric microlens arrays fabrication

Lee, Chiun Peng; Chen, Yi Hsin; Lai, Mei-Feng

doi:10.1007/s10404-013-1232-7

Cited by 11 publications

(19 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results provide understanding as well as practical guidance for novel wireless technologies for important microfluidic applications, such as micromixers, 24 cytometers or cell sorters, 4,5 biological analysis and catalysis with magnetic beads, 25,26 optofluidics devices, 27 and microlenses. 10,11 …”

Section: F Initial Particle Concentration Of Ferrofluid (I) Effectmentioning

confidence: 98%

“…4,5 Other applications include separation of diamagnetic particles, 6,7 rotating seals, 8 loudspeakers, 9 and microlens arrays. 10,11 Usually, permanent magnets [12][13][14] or electromagnets 15,16 are placed adjacent to LOC devices to produce a magnetic field gradient. Alternatively, micro magnets are directly fabricated and embedded in LOC chips by micro fabrication techniques (e.g., sputter deposition and soft-lithography) to produce magnetic (e.g., Ni) thin films with the required geometry.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spreading of a ferrofluid core in three-stream micromixer channels

et al. 2015

View full text Add to dashboard Cite

Spreading of a water based ferrofluid core, cladded by a diamagnetic fluid, in threestream micromixer channels was studied. This spreading, induced by an external magnetic field, is known as magnetofluidic spreading (MFS). MFS is useful for various novel applications where control of fluid-fluid interface is desired, such as micromixers or micro-chemical reactors. However, fundamental aspects of MFS are still unclear, and a model without correction factors is lacking. Hence, in this work, both experimental and numerical analyses were undertaken to study MFS. We show that MFS increased for higher applied magnetic fields, slower flow speed of both fluids, smaller flow rate of ferrofluid relative to cladding, and higher initial magnetic particle concentration. Spreading, mainly due to connective diffusion, was observed mostly near the channel walls. Our multi-physics model, which combines magnetic and fluidic analyses, showed, for the first time, excellent agreement between theory and experiment. These results can be useful for lab-on-a-chip devices. C 2015 AIP Publishing LLC. [http://dx.

show abstract

Section: F Initial Particle Concentration Of Ferrofluid (I) Effectmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Spreading of a ferrofluid core in three-stream micromixer channels

et al. 2015

View full text Add to dashboard Cite

show abstract

“…By solidifying the covering prepolymer and washing away noncurable ferrofluid droplets, inverse structure of the ferrofluid droplet pattern is transferred onto the polymer. Finally, the polymer is employed as the template for fabrication of microarrays with various functions such as droplet manipulation and micro‐optics . For example, Shang et al presented nepenthes peristome‐inspired anisotropic wettability surfaces based on ferrofluid assembled templates (Figure c–h) .…”

Section: Materials Derived From Ferrofluidsmentioning

confidence: 99%

“…Finally, the polymer is employed as the template for fabrication of microarrays with various functions such as droplet manipulation and micro-optics. [53][54][55] For example, Shang et al presented nepenthes peristome-inspired anisotropic wettability surfaces based on ferrofluid assembled templates (Figure 2c-h). [51] The resultant surface not only enabled a fast, continuous, controllable autonomous unidirectional water transportation, but also constructed a pump-free microfluidic device to implement multiphase flow reactions.…”

Section: Introductionmentioning

confidence: 99%

Flexible Ferrofluids: Design and Applications

et al. 2019

View full text Add to dashboard Cite

Ferrofluids, also known as ferromagnetic particle suspensions, are materials with an excellent magnetic response, which have attracted increasing interest in both industrial production and scientific research areas. Because of their outstanding features, such as rapid magnetic reaction, flexible flowability, as well as tunable optical and thermal properties, ferrofluids have found applications in various fields, including material science, physics, chemistry, biology, medicine, and engineering. Here, a comprehensive, in‐depth insight into the diverse applications of ferrofluids from material fabrication, droplet manipulation, and biomedicine to energy and machinery is provided. Design of ferrofluid‐related devices, recent developments, as well as present challenges and future prospects are also outlined.

show abstract

“…However, the above methods are complicated or not flexible enough to make microcones with tunable feature for our specific purpose. Previously, ferrofluid‐molding method, which made use of ferrofluid as the master of the mother mold, has been demonstrated to fabricate microscale polymer arrays with controllable size …”

Section: Introductionmentioning

confidence: 99%

Anisotropic Wettability of Biomimetic Micro/Nano Dual‐Scale Inclined Cones Fabricated by Ferrofluid‐Molding Method

Huang

Lai

Liu

et al. 2015

Adv Funct Materials

View full text Add to dashboard Cite

2670 wileyonlinelibrary.com water droplet; [ 6 ] trichomes on the leaf surface are arranged with orientation to direct water droplets toward one end of the leaf to conserve water; [ 7 ] the wing surface of brown lacewing (Micromus tasmaniae) with microtrichia at different length-scale allow the insect to get through the wetted surfaces. [ 8 ] The above-mentioned surface all contain microscale geometry with special arrangement or topographies to infl uence the surface property. Specifi cally, leaf surface contains various trichomes that for some incline at an acute angle to guide water [ 7 ] while others retain water on leaves to improved photosynthetic environment. [ 9 ] Inspired by the peculiar trichome structures, this study attempted to adopt cone-shaped structures to systematically understand how the inclination of the trichome infl uences the wettability of leaves.Different strategies have been reported to obtain artifi cial microcone structures for the study of wetting property, including replica moulding, [ 2b , 10 ] laser irradiation, [11][12][13] reactive ion etching (RIE), [ 14,15 ] and chemical deposition. [ 16 ] However, the above methods are complicated or not fl exible enough to make microcones with tunable feature for our specifi c purpose. Previously, ferrofl uid-molding method, which made use of ferrofl uid as the master of the mother mold, has been demonstrated to fabricate microscale polymer arrays with controllable size. [ 17 ] In this study, we utilized the similar technique and further, modifi ed it for our particular purpose ( Figure 2 ). In the experiment, microcone structures with different inclination angle were generated by adjusting the direction of external magnetic fi eld applied to the ferrofl uid. Nickel thin fi lm was then deposited to give a nanoscale roughness layer. Wettability studies (contact angle, sliding angle) were analyzed, and the retention forces of droplet move against or along the orientation of cones were investigated. Results and DiscussionTo create cone-shaped structures resembling trichomes of plants, ferrofl uid-molding method was adopted. [ 17 ] As shown in Figure 3 a, the ferrofl uid was divided into microdroplets due to magnetic hydrodynamic instability and were arranged by the magnetic disks to form a hexagonal pattern. As the external Learning from nature, a series of cone-shaped structures resembling trichomes of plants are fabricated by ferrofl uid molding to understand the infl uence of geometry on wettability. Experimentally, ferrofl uid microdroplets are generated under an external magnetic fi eld, and their shape can be changed from right cones into oblique cones by tilting the external magnetic fi eld. Followed by hard molds made with UV-curable tri(propylene glycol) diacrylate, polydimethylsiloxane microcones with different inclination angle ( θ ) are subsequently generated. Nickel thin fi lm is deposited onto the microcones to form micro/nano dual-scale structures. The largest contact angle (CA) is obtained in nickel-deposited right cones (CA = 1...

show abstract

Ferrofluid-molding method for polymeric microlens arrays fabrication

Cited by 11 publications

References 39 publications

Spreading of a ferrofluid core in three-stream micromixer channels

Spreading of a ferrofluid core in three-stream micromixer channels

Flexible Ferrofluids: Design and Applications

Anisotropic Wettability of Biomimetic Micro/Nano Dual‐Scale Inclined Cones Fabricated by Ferrofluid‐Molding Method

Contact Info

Product

Resources

About