A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• affect the boundary slip, and many previous investigations have shown that, from qualitative points of view, the positive slip length monotonically increases with the increase in the contact angle [57][58][59][60][61]. Furthermore, when studying the water flow on smooth surfaces, there is a

Effects of surface charge and boundary slip on time-periodic pressure-driven flow and electrokinetic energy conversion in a nanotube

• Mandula Buren,
• Yongjun Jian,
• Yingchun Zhao,
• Long Chang and
• Quansheng Liu

Beilstein J. Nanotechnol. 2019, 10, 1628–1635, doi:10.3762/bjnano.10.158

• nanochannels, at least one characteristic dimension of which is below or of the order of 100 nm. The decrease of length scale of the channel leads to the emergence of new phenomena different from those in macroflow, such as the electrokinetic effect and boundary slip. When wall surfaces are brought into

• tube were, respectively, by Bandopadhyay and Chakraborty [8] and Nguyen and co-workers [10]. The no-slip flow of a Maxwell fluid in a soft nanochannel and the electrokinetic energy conversion efficiency were studied by Jian and co-workers [9]. In nanoscale flow, the boundary slip effect becomes

• large for nanoscale flow. Many researchers investigated the influences of the surface charge and the boundary slip on micro- and nanoscale flows [11][12][13][14][15][16][17]. Among these, Yang and Kwok [11][12] studied time-periodic pressure-driven flows in circular and parallel-plate microchannels with

Optimal fractal tree-like microchannel networks with slip for laminar-flow-modified Murray’s law

• Dalei Jing,
• Shiyu Song,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2018, 9, 482–489, doi:10.3762/bjnano.9.46

• fluid flow in any single microchannel with boundary slip at the kth level can be expressed as follows [26] where RHk is the hydraulic resistance of fluid flow in any single microchannel at the kth level, and μ is the dynamic viscosity of the fluid flow. For the pressure-driven flow in a fractal tree

Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol

• Yifan Li,
• Yunlu Pan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2017, 8, 2504–2514, doi:10.3762/bjnano.8.250

• that can affect the drag of fluid flow. For surfaces with different oleophobicity, the boundary slip at the solid–oil interface is mostly larger than that at the solid–water interface. Roughness is a key factor for the wettability of superoleophilic/superoleophobic surfaces, and it has been found to

• significantly inhibit the degree of boundary slip on both superoleophilic surfaces in Wenzel state and superoleophobic surfaces in Cassie state immersed in oil. The oleic systems were likely to enhance boundary slip and resulted in a corresponding reduction in drag with decreasing roughness on the solid–oil

• interfaces. Keywords: boundary slip; roughness; superoleophilic; superoleophobic; Introduction In micro/nanofluidic systems, the increasing surface to volume ratio leads to unignorable fluid drag at the solid–liquid interface. The reduction of fluid drag is an important issue to improve the efficiency of

Characterization of spherical domains at the polystyrene thin film–water interface

• Khurshid Ahmad,
• Xuezeng Zhao,
• Yunlu Pan and
• Danish Hussain

Beilstein J. Nanotechnol. 2016, 7, 581–590, doi:10.3762/bjnano.7.51

• example, to study boundary slip and micro-/nanobubble formation [15][16][17][18][19]. Nanobubbles are gaseous domains that may be found at a solid–liquid interface. Over the past few decades, dedicated research has been carried out on nanobubbles at the solid–liquid interface. AFM has been proven to be a

Electroviscous effect on fluid drag in a microchannel with large zeta potential

• Dalei Jing and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2015, 6, 2207–2216, doi:10.3762/bjnano.6.226

• surface charge, boundary slip, nanobubble and surface roughness, which can be neglected in macroscale fluidics, are believed to significantly affect the micro/nano fluid flow [3][4][5][6][7][8][9][10][11][12][13]. When a droplet of certain liquid contacts with a solid surface, the solid–liquid interface

• considered when studying the electroviscous effect. Further, there is a complicated coupling relationship between the surface charge and boundary slip at the solid–liquid interface. Joly et al. [32] theoretically analyzed the effect of surface charge on the slip and established a mathematical model using

The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

• Yunlu Pan,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2014, 5, 1042–1065, doi:10.3762/bjnano.5.117

• The drag of fluid flow at the solid–liquid interface in the micro/nanoscale is an important issue in micro/nanofluidic systems. Drag depends on the surface wetting, nanobubbles, surface charge and boundary slip. Some researchers have focused on the relationship between these interface properties. In

• force on the probe were measured on an octadecyltrichlorosilane (OTS) surface with applied voltage. The influence of the surface charge on the boundary slip and drag of fluid flow has been discussed. Finally, the influence of the applied voltage on the surface wetting, nanobubbles, surface charge

• , boundary slip and the drag of liquid flow are summarized. With a smaller surface charge density which could be achieved by applying a voltage on the surface, larger and fewer nanobubbles, a larger slip length and a smaller drag of liquid flow could be found. Keywords: atomic force microscopy; boundary

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

Beilstein J. Nanotechnol. 2011, 2, 66–84, doi:10.3762/bjnano.2.9

• degree of boundary slip at the solid–liquid interface is characterized by a slip length. The slip length b is defined as the length of the vertical intercept along the axis orthogonal to the interface when a tangent line is drawn along the velocity profile at the interface (Figure 2, right). Recent

• ][43][44] and experimental studies [33][45][46][47] suggest that the presence of nanobubbles at the solid-liquid interface is responsible for boundary slip on hydrophobic surfaces. Roughness-induced superoleophobicity The surface tension of oil and organic liquids is lower than that of water, so to

• hierarchical structures show much higher slip lengths of 91 and 103 µm, respectively, which implies the boundary slip increases with increasing hydrophobicity of solid surfaces. Slip length measurements have also been made on the nanoscale on hydrophilic and hydrophobic surfaces with various degrees of