Controlling the Movement of Water Droplets With Micro- And Hierarchical Micro/Nanostructures

Rasilainen, Tiina; Kirveslahti, Anna; Nevalainen, Pauliina; Suvanto, Mika; Pakkanen, Tapani A.

doi:10.1142/s0218625x11014679

Cited by 5 publications

(3 citation statements)

References 45 publications

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“…However, for droplets moving across the surface, microcavity surfaces have been shown to possess different wetting properties from pillars even for similar surface coverage . Microcavity surfaces have been fabricated in silicon , and polymer ,, with static contact angles in the same range as for pillar surfaces.…”

Section: Introductionmentioning

confidence: 99%

Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

et al. 2014

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We study water drop roll-off at superhydrophobic surfaces with different surface patterns. Superhydrophobic microcavity surfaces were fabricated in silicon and coated with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS). For the more irregular surface patterns, the observed increase in roll-off angles is found to be caused by a decrease of the receding contact angle, which in turn is caused by an increase of the triple phase contact line of the drops for those more irregular surfaces. To understand the observation, we propose to treat the microdrops as rigid bodies and apply a torque balance between the torque exerted by the projected gravity force and the torque exerted by the adhesion force acting along the triple line on the receding side of the drop. This simple model provides a proper order of magnitude estimate of the measured effects.

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Section: Introductionmentioning

confidence: 99%

Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

et al. 2014

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“…Bump-like nanostructures were observed all around the hierarchical micro-micropillars and between them. Replication of the upper hierarchical levels is typically critical in the molding process, and adjusting the mold temperature has been considered as the most practical way to affect the filling of the mold structures [4,29]. In this study, the replication of the nanostructures on the smallest micropillars was clearly dependent on the mold temperature.…”

Section: Planar Structured Polymer Surfacesmentioning

confidence: 78%

Superhydrophobic hierarchical three-level structures on 3D polypropylene surfaces

Mielonen

Pakkanen

2019

J. Micromech. Microeng.

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Hierarchical micro-micro-nanostructures were fabricated on planar and curved polypropylene surfaces by injection molding. The metal mold insert was microstructured with a microworking robot and nanostructured with an anodization process. 3D surface curvature was based on the simple bending of the mold insert into convex and concave dome-shaped formations. Three-level structural hierarchy was demonstrated to enhance superhydrophobicity compared to two-level structures. The third structural level on top of two lower structural levels decreased the contact area between the water droplet and polymer surface, which resulted in the high contact angle (CA) of 170°, low CA hysteresis of 5° and easily sliding droplets. Microstructures can be considered to protect other hierarchical levels, and the three-level-structured surface is less susceptible to lose its superhydrophobicity compared to two-level-structured surfaces. Structuration of four length scales was realized on the curved surfaces when the curvature in millimeter scale was combined with the surface structures in two microscales and nanoscale.

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“…This observation is consistent with Wenzel’s theory that roughness on hydrophobic surfaces decreases wettability [ 47 ]. Furthermore, previous studies have shown that microstructures on PP surfaces significantly increase their WCA [ 52 , 53 , 54 ]. In addition, it is well known that low surface energies weaken cell adhesion [ 55 ].…”

Section: Discussionmentioning

confidence: 99%

Effect of Functionalization of Texturized Polypropylene Surface by Silanization and HBII-RGD Attachment on Response of Primary Abdominal and Vaginal Fibroblasts

Quiles,

Rodríguez-Contreras,

Guillem-Marti

et al. 2024

Polymers

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Soft tissue defects, such as incisional hernia or pelvic organ prolapse, are prevalent pathologies characterized by a tissue microenvironment rich in fragile and dysfunctional fibroblasts. Precision medicine could improve their surgical repair, currently based on polymeric materials. Nonetheless, biomaterial-triggered interventions need first a better understanding of the cell-material interfaces that truly consider the patients’ biology. Few tools are available to study the interactions between polymers and dysfunctional soft tissue cells in vitro. Here, we propose polypropylene (PP) as a matrix to create microscale surfaces w/wo functionalization with an HBII-RGD molecule, a fibronectin fragment modified to include an RGD sequence for promoting cell attachment and differentiation. Metal mold surfaces were roughened by shot blasting with aluminum oxide, and polypropylene plates were obtained by injection molding. HBII-RGD was covalently attached by silanization. As a proof of concept, primary abdominal and vaginal wall fasciae fibroblasts from control patients were grown on the new surfaces. Tissue-specific significant differences in cell morphology, early adhesion and cytoskeletal structure were observed. Roughness and biofunctionalization parameters exerted unique and combinatorial effects that need further investigation. We conclude that the proposed model is effective and provides a new framework to inform the design of smart materials for the treatment of clinically compromised tissues.

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Controlling the Movement of Water Droplets With Micro- And Hierarchical Micro/Nanostructures

Cited by 5 publications

References 45 publications

Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

Superhydrophobic hierarchical three-level structures on 3D polypropylene surfaces

Effect of Functionalization of Texturized Polypropylene Surface by Silanization and HBII-RGD Attachment on Response of Primary Abdominal and Vaginal Fibroblasts

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