Turning a Superhydrophilic Surface Weakly Hydrophilic: Topological Wetting States

Gao, Yurui; Zhu, Chongqin; Zuhlke, Craig; Alexander, Dennis R.; Francisco, Joseph S.; Zeng, Xiao Cheng

doi:10.1021/jacs.0c07224

Cited by 31 publications

(21 citation statements)

References 55 publications

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“…This phenomenon can be attributed to the topography of the parallel nanowalls nanotexture which has the same effect in the direction normal to the nanowalls as the closed-loop nanowalls. As reported previously by us, the topology of closed-loop nanowalls/nanochannels on a surface can introduce an unbalanced force applied to all water molecules along the triple-phase contact line (TCL) which hinders the outward diffusion of the TCL, thereby leading to the phenomenon of the topological wetting state (i.e., the water droplet is in a Wenzel state with a contact angle > 0° even when the intrinsic contact angle of the water droplet is 0°). Likewise, the parallel nanowalls here also introduce an unbalanced force on all water molecules along the TCL in parallel to the nanowalls, thereby blocking the outward diffusion and infiltration of water into the deeper valley and resulting in the IMNTH state with a nonzero contact angle (rather than the Wenzel state) even when θ in = 0°.…”

Section: Resultssupporting

confidence: 88%

“…In addition to the dependence of chemical composition, the wettability of a surface is also dependent on the physical topography of the surface . For instance, very recently, we reported that the closed-loop topology of the nanowalls/nanochannels can result in unusual wetting behavior, i.e., multiple Wenzel states with apparent contact angles > 0° on an orderly structured solid surface whose flat counterpart is superhydrophilic with a contact angle of 0° …”

Section: Introductionmentioning

confidence: 99%

“…To accommodate these much finer length scales compared to previous MD simulations, , a slab droplet/substrate system was devised and used. Five physical parameters associated with the slab droplet/substrate system were found to strongly affect the transition between various wetting states: (i) the topology of the nanotexture; (ii) the intrinsic adsorption energy ( E in ), i.e., the adsorption energy of a water molecule on the corresponding smooth surface, which is used to characterize the water–smooth surface interaction; (iii) the initial location of the droplet; (iv) the height of nanotextures ( H 1 ); and (v) the spacing between each unit of nanotextures ( W 1 ). From our MD simulations, we identified five distinct wetting states for a water droplet.…”

Section: Introductionmentioning

confidence: 99%

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Multiple Wetting–Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces

Gao

Liu

Jiang

et al. 2021

JACS Au

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Surfaces with microscale roughness can entail dual-scale hierarchical structures such as the recently reported nano/microstructured surfaces produced in the laboratory ( 32494077 Nature 2020 582 55 57 ). However, how the dual-scale hierarchical structured surface affects the apparent wetting/dewetting states of a water droplet, and the transitions between the states are still largely unexplored. Here, we report a systematic large-scale molecular dynamics (MD) simulation study on the wetting/dewetting states of water droplets on various dual-scale nano/near-submicrometer structured surfaces. To this end, we devise slab-water/slab-substrate model systems with a variety of dual-scale surface structures and with different degrees of intrinsic wettability (as measured based on the counterpart smooth surface). The dual-scale hierarchical structure can be described as “nanotexture-on-near-submicrometer-hill”. Depending on three prototypical nanotextures, our MD simulations reveal five possible wetting/dewetting states for a water droplet: (i) Cassie state; (ii) infiltrated upper-valley state; (iii) immersed nanotexture-on-hill state; (iv) infiltrated valley state; and (v) Wenzel state. The transitions between these wetting/dewetting states are strongly dependent on the intrinsic wettability ( E in ), the initial location of the water droplet, the height of the nanotextures ( H 1 ), and the spacing between nanotextures ( W 1 ). Notably, E in – H 1 and E in – W 1 diagrams show that regions of rich wetting/dewetting states can be identified, including regions where between one to five states can coexist.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multiple Wetting–Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces

Gao

Liu

Jiang

et al. 2021

JACS Au

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“…The surface topological structure has been reported to affect the hydrophilic–hydrophobic properties of a material’s surface . Therefore, the contact angle of each microgrooved PLGA material was measured using a contact angle instrument, and the results are shown in Figure .…”

Section: Results and Discussionmentioning

confidence: 99%

Regulation of Myogenic Differentiation by Topologically Microgrooved Surfaces for Skeletal Muscle Tissue Engineering

et al. 2021

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Inspired by the natural topological structure of skeletal muscle tissue, the topological surface construction of bionic scaffolds for skeletal muscle repair has attracted great interest. Many previous studies have focused on the effects of the topological structure on myoblasts. However, these studies used only specific repeating sizes and shapes to achieve the myoblast alignment and myotube formation; moreover, the regulatory effects of the size of a topological structure on myogenic differentiation are often neglected, leading to a lack of guidance for the design of scaffolds for skeletal muscle tissue engineering. In this study, we fabricated a series of microgroove topographies with various widths and depths via a combination of soft lithography and melt-casting and studied their effects on the behaviors of skeletal muscle cells, especially myogenic differentiation, in detail. Microgrooved poly(lacticco-glycolic acid) substrates were found to effectively regulate the proliferation, myogenic differentiation, and myotube formation of C2C12 cells, and the degree of myogenic differentiation was significantly dependent on signals in response to the size of the microgroove structure. Compared with their depth, the width of the microgroove structures can more strongly affect the myogenic differentiation of C2C12 cells, and the degree of myoblast differentiation was enhanced with increasing groove width. Microgroove structures with relatively large groove widths and small groove depths promoted the myogenic differentiation of C2C12 cells. In addition, the integrin-mediated focal adhesion kinase signaling pathway and MAPK signaling pathway were activated in cells in response to the external topological structure, and the size of the topological structure of the material surface effectively regulated the degree of the cellular response to the external topological structure. These results can guide the design of scaffolds for skeletal muscle tissue engineering and the construction of effective bionic scaffold surfaces for skeletal muscle regeneration.

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“…Molecular dynamics (MD) simulation is a powerful tool to obtain the microscopic details of atomistic system, and it has been widely used to investigate the physiochemistry of surface and the wetting behaviors [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] . One of the key issue in MD simulation is the potential models adopted to describe the interaction between molecules.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of Wetting Behavior: Contact Angle Dependency on Water Potential Models

Hakim

Kurniawan

Indahyanti³

et al. 2021

ICS Phys. Chem.

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The underlying principle of surface wettability has obtained great attentions for the development of novel functional surfaces. Molecular dynamics simulations has been widely utilized to obtain molecular-level details of surface wettability that is commonly quantified in term of contact angle of a liquid droplet on the surface. In this work, the sensitivity of contact angle calculation at various degrees of surface hydrophilicity to the adopted potential models of water: SPC/E, TIP4P, and TIP5P, is investigated. The simulation cell consists of a water droplet on a structureless surface whose hydrophilicity is modified by introducing a scaling factor to the water-surface interaction parameter. The simulation shows that the differences in contact angle described by the potential models are systematic and become more visible with the increase of the surface hydrophilicity. An alternative method to compute a contact angle based on the height of center-of-mass of the droplet is also evaluated, and the resulting contact angles are generally larger than those determined from the liquid-gas interfacial line.

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Turning a Superhydrophilic Surface Weakly Hydrophilic: Topological Wetting States

Cited by 31 publications

References 55 publications

Multiple Wetting–Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces

Multiple Wetting–Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces

Regulation of Myogenic Differentiation by Topologically Microgrooved Surfaces for Skeletal Muscle Tissue Engineering

Molecular Dynamics Simulation of Wetting Behavior: Contact Angle Dependency on Water Potential Models

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