Aggregation and deposition of colloidal particles: Effect of surface properties of collector beads

Sadri, Behnam; Pernitsky, David; Sadrzadeh, Mohtada

doi:10.1016/j.colsurfa.2017.07.041

Cited by 21 publications

(9 citation statements)

References 24 publications

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“…However, there have been several puzzling phenomena that cannot be explained by such a classical crystallization mechanism. Recently, many researchers have reported an experimental evidence that many crystals including thin films grow by the building block of nanoparticles (NPs), which has been called 'non-classical crystallization' [16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

2020

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This study is based on the film growth by non-classical crystallization, where charged nanoparticles (NPs) are the building block of film deposition. Extensive studies about the generation of charged NPs and their contribution to film deposition have been made in the chemical vapor deposition (CVD) process. However, only a few studies have been made in the physical vapor deposition (PVD) process. Here, the possibility for Ti films to grow by charged Ti NPs was studied during radio frequency (RF) sputtering using Ti target. After the generation of charged Ti NPs was confirmed, their influence on the film quality was investigated. Charged Ti NPs were captured on amorphous carbon membranes with the electric bias of −70 V, 0 V, +5 V, +15 V and +30 V and examined by transmission electron microscopy (TEM). The number density of the Ti NPs decreased with increasing positive bias, which showed that some of Ti NPs were positively charged and repelled by the positively biased TEM membrane. Ti films were deposited on Si substrates with the bias of −70 V, 0 V and +30 V and analyzed by TEM, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR). The film deposited at −70 V had the highest thickness of 180 nm, calculated density of 4.974 g/cm3 and crystallinity, whereas the film deposited at +30 V had the lowest thickness of 92 nm, calculated density of 3.499 g/cm3 and crystallinity. This was attributed to the attraction of positively charged Ti NPs to the substrate at −70 V and to the landing of only small-sized neutral Ti NPs on the substrate at +30 V. These results indicate that the control of charged NPs is necessary to obtain a high quality thin film at room temperature.

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Section: Introductionmentioning

confidence: 99%

Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

2020

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“…Membrane fouling has been intensely studied 9,12,13 and various mechanisms of membrane fouling have been identified. Amongst the various mechanisms, cake layer/gel formation 14–16 and pore blocking 17,18 are usually regarded as the major fouling mechanisms; cake-layer formation occurs at the upstream end of the membrane, while pore blocking occurs at the pore-scale of the membrane 19–21 .…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a large number of studies has been devoted to elucidating the transport of particle-laden flow in a porous media 11,12,24–26 . In this regard, microfluidic mimics of membranes have become an important experimental platform for investigating fouling at the pore-scale 11,24,25 .…”

Section: Introductionmentioning

confidence: 99%

Investigating fouling at the pore-scale using a microfluidic membrane mimic filtration system

Debnath

Kumar

Thundat

et al. 2019

Sci Rep

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The work investigates fouling in a microfluidic membrane mimic (MMM) filtration system for foulants such as polystyrene particles and large polymeric molecules. Our MMM device consists of a staggered arrangement of pillars which enables real-time visualization and analysis of pore-scale phenomena. Different fouling scenarios are investigated by conducting constant-pressure experiments. Fouling experiments are performed with three different types of foulants: polystyrene particle solution (colloidal fouling), polyacrylamide polymer solution (organic fouling) and a mixture of these two solutions (combined fouling). Four major categories of microscopic fouling are observed: cake filtration (upstream), pore blocking (inside the pores), colloidal aggregation (downstream) and colloidal streamer fouling (downstream). Our microfluidic experiments show that downstream colloidal aggregation and streamer fouling have a significant effect on overall membrane fouling which were not studied before.

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“…This new growth mechanism was supported by many experimental evidences. This new mechanism is referred to as "non-classical crystallization" [16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pressure on the Film Deposition during RF Magnetron Sputtering Considering Charged Nanoparticles

et al. 2021

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Non-classical crystallization, in which charged nanoparticles (NPs) are the building blocks of film growth, has been extensively studied in chemical vapor deposition (CVD). Recently, a similar mechanism of film growth has been reported during radio frequency (RF) sputtering with a Ti target and DC magnetron sputtering using an Ag target. In this study, the effect of pressure on the generation of Ti NPs and on the film deposition was studied during RF sputtering with a Ti target. Ti NPs were captured on transmission electron microscopy (TEM) membranes with the electric biases of −30, 0, and +50 V under 20 and 80 mTorr. The number densities of the Ti NPs were 134, 103, and 21 per 100 × 100 nm2, respectively, with the biases of −30, 0, and +50 V under 20 mTorr and were 196, 98, and 0 per 100 × 100 nm2, respectively, with the biases of −30, 0, and +50 V under 80 mTorr, which was analyzed by TEM. The growth rate of Ti films deposited on Si substrates was insensitive to the substrate bias under 20 mTorr but was sensitive under 80 mTorr, with the thicknesses of 132, 133, 97, and 29 nm, respectively, after being deposited for 15 min with the substrate biases of −30, −10, 0, and +50 V. This sensitive dependence of the film growth rate on the substrate bias under 80 mTorr is in agreement with the sensitive dependence of the number density of Ti NPs on the substrate bias under 80 mTorr.

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Aggregation and deposition of colloidal particles: Effect of surface properties of collector beads

Cited by 21 publications

References 24 publications

Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

Investigating fouling at the pore-scale using a microfluidic membrane mimic filtration system

Effect of Pressure on the Film Deposition during RF Magnetron Sputtering Considering Charged Nanoparticles

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