scholarly journals Facile Preparation of a Superhydrophobic iPP Microporous Membrane with Micron-Submicron Hierarchical Structures for Membrane Distillation

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 962 ◽  
Author(s):  
Cuicui Hu ◽  
Zhensheng Yang ◽  
Qichao Sun ◽  
Zhihua Ni ◽  
Guofei Yan ◽  
...  
Keyword(s):  
Large Scale ◽  
Hierarchical Structures ◽  
High Water ◽  
Membrane Distillation ◽  
New Method ◽  
Water Contact ◽  
Lotus Effect ◽  
Thermally Induced ◽  
Vacuum Membrane Distillation ◽  
Micro Structures

A facile method combining micro-molding with thermally-induced phase separation (TIPS) to prepare superhydrophobic isotacticpolypropylene (iPP) microporous membranes with micron-submicron hierarchical structures is proposed in this paper. In this study, the hydrophobicity of the membrane was controlled by changing the size of micro-structures on the micro-structured mold and the temperature of the cooling bath. The best superhydrophobicity was achieved with a high water contact angle (WCA) of 161° and roll-off angle of 2°, which was similar to the lotus effect. The permeability of the membrane was greatly improved and the mechanical properties were maintained. The membrane prepared by the new method and subjected to 60h vacuum membrane distillation (VMD) was compared with a conventional iPP membrane prepared via the TIPS process. The flux of the former membrane was 31.2 kg/m2·h, and salt rejection was always higher than 99.95%, which was obviously higher than that of the latter membrane. The deposition of surface fouling on the former membrane was less and loose, and that of the latter membrane was greater and steady, which was attributed to the micron-submicron hierarchical structure of the former and the single submicron-structure of the latter. Additionally, the new method is expected to become a feasible and economical method for producing an ideal membrane for membrane distillation (MD) on a large scale.

Preparation of Hydrophobic Microporous Polypropylene/Isotactic Polypropylene Blending Membranes via Thermally Induced Phase Separation for Vacuum Membrane Distillation

2013 ◽  
Vol 790 ◽  
pp. 81-84 ◽  
Author(s):  
Na Tang ◽  
Shuang Zhang ◽  
Lei Zhang ◽  
Peng Gao Cheng ◽  
Jin Jin Li
Keyword(s):  
Phase Separation ◽  
Isotactic Polypropylene ◽  
Membrane Distillation ◽  
Mass Ratio ◽  
Thermally Induced Phase Separation ◽  
Nacl Solution ◽  
Optimum Conditions ◽  
Thermally Induced ◽  
Vacuum Membrane Distillation ◽  
Feed Temperature

The hydrophobic microporous membranes were prepared from a blend system by thermally induced phase separation (TIPS) process. The polymer blend system was isotactic polypropylene (iPP)/ high-density polyethylene (HDPE) and the diluent was soybean oil. The effects of the mass ratio of iPP and HDPE and the initial concentration of blending on the membranes structure were both investigated. Additionally, the influence of the feed temperature and the feed rate on the VMD performance of iPP/HDPE blend membranes was also investigated. For 0.5M aqueous NaCl solution, the VMD flux and reject ratio of the membranes reached 8.7kg/(m2·h) and nearly 100% under the optimum conditions (mass ration of iPP/HDPE was 6:1, and intial blend concentration was 38%), respectively.

Superhydrophobic Nanocrystalline Nickel Films Inspired by Lotus Leaf

2008 ◽  
Vol 1132 ◽  
Author(s):  
Mehdi Shafiei ◽  
Ahmet T. Alpas
Keyword(s):  
Contact Angle ◽  
Grain Size ◽  
Surface Structure ◽  
Water Contact Angle ◽  
Surface Texture ◽  
High Water ◽  
New Method ◽  
Water Contact ◽  
Lotus Leaf ◽  
Tip Radius

ABSTRACTA new method to fabricate superhydrophobic hard films is described. Surface texture of lotus leaf was replicated on an acetate film, on which a nanocrystalline (NC) Ni coating with a grain size of 30 ± 4 nm and a hardness of 4.42 GPa was electrodeposited. The surface texture consisted of conical protuberances with a height of 10.0 ± 2.0 0m and a tip radius of 2.5 ± 0.5 0m. An additional electrodeposition for 120 s and 300 s was used to locally modify the surface structure by depositing ‘Ni crowns' on the protuberances that increased their height to 14.0 ± 2.0 0m and their tip radius to 6.0 ± 0.5 0m. The modified structures were then treated with a perfluoropolyether (PFPE) solution, which provided a high water contact angle of 156°, i.e., comparable to the naturally superhydrophobic lotus leaf. The increased hydrophobicity as a result of surface structure and chemistry modifications was evident compared to a smooth NC Ni sample, which had a contact angle of 64°.

scholarly journals Femtosecond Laser Produced Hydrophobic Hierarchical Structures on Additive Manufacturing Parts

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 601 ◽  
Author(s):  
Lishi Jiao ◽  
Zhong Chua ◽  
Seung Moon ◽  
Jie Song ◽  
Guijun Bi ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Photoelectron Spectroscopy ◽  
Hierarchical Structures ◽  
Hydrophobic Surface ◽  
Functional Surface ◽  
Sem Images ◽  
Water Contact ◽  
Fs Laser ◽  
Micro Structures

With the recent expansion of additive manufacturing (AM) in industries, there is an intense need to improve the surface quality of AM parts. A functional surface with extreme wettability would explore the application of AM in medical implants and microfluid. In this research, we propose to superimpose the femtosecond (fs) laser induced period surface structures (LIPSS) in the nanoscale onto AM part surfaces with the micro structures that are fabricated in the AM process. A hierarchical structure that has a similar morphology to a lotus leaf surface is obtained by combining the advantages of liquid assisting fs laser processing and AM. A water contact angle (WCA) of 150° is suggested so that a super hydrophobic surface is achieved. The scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) analysis indicate that both hierarchical structures and higher carbon content in the laser processed area are responsible for the super hydrophobicity.

Functionalization of technical textile tapes

2018 ◽  
Vol 2 (89) ◽  
pp. 72-84
Author(s):  
W. Urbaniak-Domagała ◽  
E. Kobierska
Keyword(s):  
Hydrophobic Effect ◽  
Hierarchical Structures ◽  
High Water ◽  
Contact Angles ◽  
Slow Increase ◽  
Water Contact ◽  
Reduced Pressure ◽  
Dry Process ◽  
Hydrophobic Barrier ◽  
Fabric Surface

Purpose: The aim of the study was to deposit a hydrophobic barrier coating on technical tapes in order to protect them from water and to test and assess the obtained products. Design/methodology/approach: The coatings were deposited on elastic, textile substrates using PACVD of hexamethyldisiloxane vapours with an RF commercial plasma system under reduced pressure. Findings: The coatings increased the hydrophobicity of the technical tapes, which was confirmed by high water contact angles and reduced water sorption by the tape. The polymerization of the monomer vapour plasma was achieved without carrier gas. With a relatively slow increase in the deposition, rough coatings were obtained on a submicroscopic level, as opposed to the commonly produced smooth ppHMDSO coatings. This rough character enhanced the hydrophobicity of the surface according to the Wetzel or Cassie models. The modification processes did not significantly affect the basic mechanical properties of the tapes, such as Young’s modulus and tensile strength. The ppHMDSO coatings are resistant to aging and mechanical wear and retain their hydrophobic barrier properties. Research limitations/implications: The quantitative assessment of the wettability of a substrate with a rough surface is difficult and often ambiguous. This element of physicochemical metrology is wide open for innovation. Practical implications: The use of this plasma technique to make textile barrier products shows several merits, such as an economically justifiable, pro-ecological and dry process. The hydrophobicity of the textile substrates can also be obtained using other monomers. Originality/value: The formation of local hierarchical structures on the top layer of the fabric surface enhance the hydrophobic effect.

ECTFE porous membranes with conveniently controlled microstructures for vacuum membrane distillation

2015 ◽  
Vol 3 (46) ◽  
pp. 23549-23559 ◽  
Author(s):  
Jian Pan ◽  
Changfa Xiao ◽  
Qinglin Huang ◽  
Hailiang Liu ◽  
John Hu
Keyword(s):  
Phase Separation ◽  
Membrane Distillation ◽  
Diethyl Phthalate ◽  
Porous Membranes ◽  
Microporous Membranes ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Vacuum Membrane Distillation ◽  
Poly Ethylene

Poly(ethylene chlorotrifluoroethylene) (ECTFE) microporous membranes were prepared via a thermally induced phase separation (TIPS) process using a mixed diluent of bis(2-ethylhexyl) adipate (DEHA) and diethyl phthalate (DEP).

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