Formation of liquid marbles &amp; aggregates: rolling and electrostatic formation using conductive hexagonal plates

Lobel, Benjamin T.; Fujiwara, Junya; Fujii, Syuji; Thomas, Casey A.; Ireland, Peter M.; Wanless, Erica J.

doi:10.1039/d0ma00670j

Cited by 12 publications

(19 citation statements)

References 57 publications

(133 reference statements)

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“…Glass/ PPy-C 8 F were synthesized via a multistage synthetic method similar to that used in a previous work on a polyethylene terephthalate substrate. 9 Briefly, 63−90 μm glass particles (6.0 g) were placed in 2propanol (20 g, Sigma-Aldrich), which contained 3-glycidoxypropyltriethoxysilane (0.3 g, Shin-Etsu Chemical Co., Ltd), and then allowed to stir for 30 min at 35 °C, followed by evaporation of 2propanol using an evaporator at 35 °C. After the evaporation of 2propanol, the particles were left to dry under vacuum (45.9 Pa) for 24 h and then dispersed once more in 2-propanol, followed by washing via filtration.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…20,23−26 The electrostatic method of liquid marble formation using an electric field is a potential remedy for this engineering hurdle. 6,7,9,11 This technique is underpinned by direct delivery of particulate matter to a pendent droplet without direct contact between the droplet and the particle reservoir using an electrostatic field. 6,11 This allows for the formation of liquid marbles of controllable size, coating, and composition using a range of materials.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Electrostatic particle processing is of growing interest in both research and industrial arenas. − A particularly interesting example is the formation of liquid marbles; liquid droplets armored by adsorbed nonwetting particles. − Once encapsulated, these liquid marbles demonstrate remarkable elasticity , and locomotive properties while retaining gas permeability. ,, These structures have been of substantial research interest for the last 20 years since they were first reported by Aussillous and Quéré. , Some proposed applications of these structures have included their use as microreactors for rapid blood typing and chemical detection, − as well as a microvessel for targeted payload delivery. − However, their implementation in many proposed applications is hindered due to the lack of scalable and controllable mass production techniques. ,− The electrostatic method of liquid marble formation using an electric field is a potential remedy for this engineering hurdle. ,,, This technique is underpinned by direct delivery of particulate matter to a pendent droplet without direct contact between the droplet and the particle reservoir using an electrostatic field. , This allows for the formation of liquid marbles of controllable size, coating, and composition using a range of materials. − Studies of this particular technique have focused on a variety of materials including polymers such as polystyrene and conductive hydrophobic particles. , Investigation of nonconducting or dielectric hydrophobic particles has been limited to date. Previous work using cinnamon particles revealed an unusually large (μm), and uniform interparticle spacing on the pendent droplet surface upon initial particle transfer .…”

Section: Introductionmentioning

confidence: 99%

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Interparticle Repulsion of Microparticles Delivered to a Pendent Drop by an Electric Field

et al. 2021

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We report an unusually large spacing observed between microparticles after delivery to the surface of a pendent water droplet using a DC nonuniform electrostatic field, primarily via dielectrophoresis. The influence of particle properties was investigated using core particles, which were either coated or surface-modified to alter their wettability and conductivity. Particles that exhibited this spacing were both hydrophobic and possessed some dielectric material exposed to the external field, such as a coating or exposed dielectric core. The origin of this behavior is proposed to be the induced dipole–dipole repulsion between particles, which increases with particle size and decreases when the magnitude of the electric field is reduced. When the particles were no longer subjected to an external field, this large interparticle repulsion ceased and the particles settled to the bottom of the droplet under the force of gravity. We derive a simple model to predict this spacing, with the dipole–dipole repulsion balanced against particle weight. The external electric field was calculated using the existing electric field models. The spacing was found to be dependent on particle density and the induced dipole moment as well as the number of particles present on the droplet interface. As the number of particles increased, a decrease in interparticle spacing was observed.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interparticle Repulsion of Microparticles Delivered to a Pendent Drop by an Electric Field

et al. 2021

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“…Transparent hydrophobic PET plates were prepared via surface modification using FSCA, as previously described, , and were denoted as PET-FSCA [Figure a(i)]. PPy-coated hydrophobic PET plates (PET-PPy-FSCA) with photothermal properties were fabricated based on the method modified from previous one [Figure a(ii)] . Briefly, the PET plates (50.0 g) were dispersed in an IPA (120 g) solution of 3-glycidoxypropyltriethoxysilane (0.3 g) and were left for 30 min at 35 °C with stirring, followed by removal of the IPA medium using a rotary evaporator and then a decompression dryer (45.9 Pa) for 24 h. The PET plates were again dispersed in IPA, followed by purification via filtration and drying at 25 °C for 24 h and then at 80 °C for 24 h. These plates carrying epoxy groups on their surfaces (PET-SCA plates, 40 g) were dispersed in water (120 g) containing NaHSO 3 (4.67 g) and were left for 6 h at 70 °C in an oil bath under a nitrogen atmosphere in order to introduce sulfonate groups via a ring-opening reaction of the epoxy groups (PET-SCA-SO 3 ‑ plates) .…”

Section: Methodsmentioning

confidence: 99%

Controllable Positive/Negative Phototaxis of Millimeter-Sized Objects with Sensing Function

et al. 2021

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Phototaxis, which is the directional motion toward or away from light, is common in nature and inspires development of artificial light-steered active objects. Most of the light-steered objects developed so far exhibit either positive or negative phototaxis, and there are few examples of research on objects that exhibit both positive and negative phototaxis. Herein, small objects showing both positive and negative phototaxis on the water surface upon near-infrared (NIR) light irradiation, with the direction controlled by the position of light irradiation, are reported. The millimeter-sized tetrahedral liquid marble containing gelled water coated by one polymer plate with light-to-heat photothermal characteristic, which adsorbs onto the bottom of the liquid marble, and three polymer plates with highly transparent characteristic, which adsorb onto the upper part of the liquid marble, is utilized as a model small object. Light irradiation on the front side of the object induces negative phototaxis and that on the other side induces positive phototaxis, and the motion can be controlled to 360° arbitrary direction by precise control of the light irradiation position. Thermographic studies confirm that the motions are realized through Marangoni flow generated around the liquid marble, which is induced by position-selective NIR light irradiation. The object can move centimeter distances, and numerical analysis indicates that average velocity and acceleration are approximately 12 mm/s and 71 mm/s2, respectively, which are independent of the direction of motions. The generated force is estimated to be approximately 0.4 μN based on Newton’s equation. Furthermore, functional cargo can be loaded into the inner phase of the small objects, which can be delivered and released on demand and endows them with environmental sensing ability.

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“…Apart from this, agitation using electrostatic forces have also been explored [14,15]. Janus liquid marbles (JLM) can be made to possess multi-response characteristics, such as being transportable on solid substrates and liquid water surfaces by magnetic forces, as well as the propensity for rupture upon exposure to either infrared radiation or acidic/basic vapors [16].…”

Section: Introductionmentioning

confidence: 99%

Brushed creation of liquid marbles

Lin

Song

Ong

et al. 2022

Preprint

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A method where particulates are transferred via a cosmetic brush onto liquid drops created on a highly non-wetting substrate with a hole to generate talc and graphite liquid marbles (LMs) and talc-graphite Janus liquid marbles is described. van der Waals forces facilitated the attachment of particulates to the dry brush bristles. Subsequently, the surface tension forces arising from particle interaction with water (which were O(102) higher than the van der Waals forces) engendered transfer of the particulates to the liquid-gas interface of the drop. Forces below 1 mN applied by a dangling foil on the LM ensured preservation of the drop shape when the force was removed. During the application of this force, the contact angles at the contact lines behaved differently from sessile drops that are inclined on surfaces. This preparation method portends the ability to automate the creation of LMs and Janus LMs for various applications.

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Formation of liquid marbles & aggregates: rolling and electrostatic formation using conductive hexagonal plates

Abstract: Conductive polymer coatings were successfully adsorbed to hexagonal polyethylene terepthalate plate surfaces after silane coupling and sulfonation were performed to promote intermolecular adhesion. Conducting particle coatings were verified via scanning...

Cited by 12 publications

References 57 publications

Interparticle Repulsion of Microparticles Delivered to a Pendent Drop by an Electric Field

Interparticle Repulsion of Microparticles Delivered to a Pendent Drop by an Electric Field

Controllable Positive/Negative Phototaxis of Millimeter-Sized Objects with Sensing Function

Brushed creation of liquid marbles

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