Aspects of Particle Adhesion and Removal

Quesnel, David J.; Rimai, D. S.; Schaefer, David; Beaudoin, Stephen P.; Harrison, Aaron J.; Hoss, Darby J.; Sweat, Melissa L.; Thomas, Myles C.

doi:10.1016/b978-0-323-29960-2.00004-6

Cited by 6 publications

(7 citation statements)

References 75 publications

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“…Particle size (in the 1–90 μm size range explored in this study) was not observed to strongly affect particle physics or adhesion behavior. This finding is consistent with work of other authors, as the particles were either smaller or similar in size to topographical surface features on the wipes and substrates and were small enough that van der Waals interactions would be expected to dominate over gravitational effects (see, e.g., Quesnel et al). Due to resolution limits inherent in optical systems, the in situ visualization system developed here is best suited for visualizing the motions of particles larger than 10 μm because at this size range particles can be distinguished from one another in the field of view, and rolling and sliding motions can also be distinguished.…”

Section: Resultsmentioning

confidence: 99%

In Situ Visualization of Particle Motions during Wipe Sampling of Explosives and Other Trace Particulate Materials

Liddell

Merrill

2019

ACS Appl. Mater. Interfaces

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Surface texture tailoring has the potential to increase the effectiveness of dry particle collection wipes, as a wipe’s topographical features control the intimate surface contact made with particles on the substrate (critical for van der Waals-governed adhesion). However, texture-tailoring approaches have not yet been widely explored, in part because of a lack of understanding of the specific wipe topographies and wipe/particle interactions that maximize particle collection. Here we describe an in situ optical microscopy technique that enables direct observation of micrometer-scale particle–wipe interactions occurring at the wipe–substrate interface during contact sampling. The technique is demonstrated for nonwoven meta-aramid (Nomex) collection wipes with particles ranging from 1 to 90 μm in diameter and substrates of different topographies (glass and nylon coil zipper). Experiments with hemispherically coated Janus particles allow rolling motions to be distinguished from sliding motions, providing detailed information about how particles move prior to capture or release by the wipe. Particle–fiber and particle–particle interactions are seen to play important roles in particle capture, suggesting that conventional sphere-on-plane models are inadequate to describe adhesion behavior in these systems. Micrographs show how loose, flexible fibers in roughened textile wipes interrogate the valleys of uneven substrate topographies, allowing capture of particles that might otherwise be trapped within the substrate’s grooves and depressions. The materials used in this work are specifically relevant to explosives detection, but the in situ visualization technique is transferable for the study of any application involving dry particle collection, such as toxic substance sampling and dust removal.

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Section: Resultsmentioning

confidence: 99%

In Situ Visualization of Particle Motions during Wipe Sampling of Explosives and Other Trace Particulate Materials

Liddell

Merrill

2019

ACS Appl. Mater. Interfaces

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“…For the adhesive force that hinders PR particles from detachment, we have considered the van der Waals force. The van der Waals force can be generally calculated by 11,30 = F AR h 6 vdW p 2 (3) where A is the Hamaker constant and h is the particle−surface separation distance in contact (generally taken as ∼0.16 nm). 31−34 The Hamaker constants of polymers are typically in between 1.0 × 10 −19 J and 1.0 × 10 −20 J.…”

Section: Theoretical Approachmentioning

confidence: 99%

“…For the adhesive force that hinders PR particles from detachment, we have considered the van der Waals force. The van der Waals force can be generally calculated by , where A is the Hamaker constant and h is the particle–surface separation distance in contact (generally taken as ∼0.16 nm). − The Hamaker constants of polymers are typically in between 1.0 × 10 –19 J and 1.0 × 10 –20 J. ,, Since PR resin in this experiment has a structure comparable to that of PS, the Hamaker constant of PS (7.0 × 10 –20 J) , was selected as a representative value for the simple magnitude calculation. For the hydrodynamic forces, drag force and hydrodynamic torque in a laminar flow region can be expressed as , and where μ is the fluid viscosity and V p is the relative fluid velocity at the center of the particle.…”

Section: Theoretical Approachmentioning

confidence: 99%

Removal Analysis of Residual Photoresist Particles Based on Surface Topography Affected by Exposure Times of Ultraviolet and Developer Solution

et al. 2022

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Particle removal from the surface of a substrate has been an issue in numerous fields for a long time. In semiconductor processes, for instance, the formation of clean surfaces by removing photoresist (PR) must be followed in order to create neat patterns. Although PR removal has been intensively investigated recently, little is known about how ultraviolet (UV) and developer solutions alter the PR resin (and in what manner) near the surface. While varying the exposure times of UV and developer solution, we investigated the topographic changes on the surfaces of PR resin films and particles. The measured surface properties were then correlated with the detachment force determined using films, and eventually with the residual PR particle removal percentages obtained in a microchannel. Using a positive PR and a base developer solution, we demonstrated that UV causes the surface of PR resin to become hydrophilic and wavy, whereas the developer solution produces a surface with a larger degree of roughness by swelling and partially dissolving the resin. Ultimately, the increased roughness decreased the effective contact area between PR resins, hence decreasing the detachment force and increasing the particle removal percentages. We anticipate that our findings will help understand residual particle issues, particularly on the removal mechanism of PR resins based on surface topography.

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“…Primarily, the dominant forces of nature that determine the interaction between the particle and substrate depends on the size of the particle and the respective distance of separation amongst them. The adhesion of particles arises from the existence of attractive forces between the particle-substrate coupled with the mechanical response to this adhesion, that is the stress caused due to the deformation which determines the intensity of the bonded particle to the surface [17]. For the two tests conducted with varying particle diameter, it was observed that the cleaning efficiency for the sand (~300 μm) deposited layer was distinctively higher as seen in Figure 8 compared to the dust (~45 μm).…”

Section: Effectiveness Of Cleaningmentioning

confidence: 99%

“…As the operating frequency approached the 1 st natural frequency, any overlay of the dust thickness was reduced, leaving a fine layer of dust on the surface. This is explained in the literature [4] [17] as the Van der Waals forces between the particles of the dust can be excited from low frequencies but due to the large surface area of the substrate and reduced particle size (<45 μm), the electrostatic forces of attraction are relatively high for the particle-substrate that causes the dust to adhere to the surface. As for the sand particles, the gravitational force = 1.33 3 becomes a relevant factor, since the radius of the particle is dependent by a factor of 3.…”

Section: Effectiveness Of Cleaningmentioning

confidence: 99%

Cymatics Inspired Self-Cleaning Mechanism for Solar Panels

Babu

Yesudasan

Chacko

2020

Preprint

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The Photovoltaic modules are usually installed on the ground which exposes it to surface deposition of foreign particles. In the Middle East and North Africa region, the primary culprit is dust and sand. They form an insulating and opaque layer on the surface of the glass, which obstructs its heat transfer and optical properties, thereby reducing the overall yield efficiency of the solar panel. Cleaning of this layer is critical to the operation of the solar panel and often requires great effort and energy on a large-scale solar array. In this paper, we propose a novel self-cleaning mechanism for solar panels, with an understanding of the structural integrity of the Photovoltaic laminate and application of external mechanical vibration. By applying an external source of vibration, the solar panels vibrate, excites its fundamental frequencies and cleans by its own. The method is analyzed using finite element analysis method and tested using experiments. Our simulation results based on IEC 61215 show that the maximum principal stress and deformation in the critical layers is within limits. Our experimental results prove the proposed theory is feasible and can be extended to large scale solar arrays. Our proposed method is retrofittable and could save money, energy and effort in cleaning the solar arrays, which can replace current techniques.

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Aspects of Particle Adhesion and Removal

Cited by 6 publications

References 75 publications

In Situ Visualization of Particle Motions during Wipe Sampling of Explosives and Other Trace Particulate Materials

In Situ Visualization of Particle Motions during Wipe Sampling of Explosives and Other Trace Particulate Materials

Removal Analysis of Residual Photoresist Particles Based on Surface Topography Affected by Exposure Times of Ultraviolet and Developer Solution

Cymatics Inspired Self-Cleaning Mechanism for Solar Panels

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