Hierarchically porous membranes with isolated-round-pores connected by narrow-nanopores: A novel solution for trade-off effect in separation

Wang, Jiayao; Ding, Mingming; Cheng, Xiaoqing; Ye, Cuicui; Li, Fēi; Li, Yongjin; You, Jichun

doi:10.1016/j.memsci.2020.118040

Cited by 29 publications

(20 citation statements)

References 39 publications

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“…The bi-continuous structures including the crystal framework and the amorphous components of polymer blend systems have been validated in our previous work [13,14,27,[36][37][38][39]. Based on this model, a novel strategy has been developed to fabricate porous structures upon etching with selective solvent.…”

Section: Resultsmentioning

confidence: 92%

“…The increase in crystallization temperature is beneficial for the inclusion of TAIC, accounting for its migration to the amorphous regions in PLLA spherulites for the bigger pores shown in Figure 4C. [13,14,27,[36][37][38][39]. Based on this model, a novel strategy has been developed to fabricate porous structures upon etching with selective solvent.…”

Section: Resultsmentioning

confidence: 99%

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Inclusion/Exclusion Behaviors of Small Molecules during Crystallization of Polymers in Miscible PLLA/TAIC Blend

et al. 2022

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In this work, PLLA/TAIC has been taken as a model system to investigate the inclusion and exclusion of small molecules during the crystallization of polymers in their miscible blend. Our results indicate that it is the growth rate and diameter of PLLA spherulites that dominate the localization of TAIC. On the one hand, crystallization temperature plays an important role. Crystallization at higher temperature corresponds to higher growth rates and a greater diameter of PLLA spherulites. The former improves the ability of PLLA crystals to trap TAIC while the latter leads to a lower volume fraction of space among neighboring PLLA spherulites. The combination of the two contributes to the enhanced inclusion behaviors. On the other hand, when compared to melt crystallization, cold crystallization results in much smaller spherulites (from higher nucleation density) and sufficient space among spherulites, which accounts for the enrichment of TAIC in interspherulitic regions and for its enhanced exclusion. In the adopted polymer–small molecule blend, TAIC can enrich in interspherulitic regions even in its miscible blend with PLLA, which can be attributed to its stronger diffusion ability.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Inclusion/Exclusion Behaviors of Small Molecules during Crystallization of Polymers in Miscible PLLA/TAIC Blend

et al. 2022

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“…In the fabrication of porous PVDF spheres, therefore, PMMA acts as the agency for narrow nanopores. On these spheres, there are narrow pores in nanometers ( Figure 1 C) that resulted from the exclusion behaviors of PMMA during the crystallization of PVDF (i.e., narrow pores from the crystallization template) [ 24 , 25 , 26 ]. The PLLA film with a thickness of 300 μm was prepared by means of hot-pressing.…”

Section: Resultsmentioning

confidence: 99%

Programmable Transition between Adhesive/Anti-Adhesive Performances on Porous PVDF Spheres Supported by Shape Memory PLLA

et al. 2022

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Superhydrophobic surfaces with switchable adhesive/anti-adhesive performances are highly desired but still challenging. Herein, by loading porous poly (vinylidene fluoride) (PVDF) spheres on a shape memory polylactic acid (PLLA) film, a quasi-superhydrophobic surface of composite film (PVDF@PLLA) with the ability to tailor its surface structures/composition and related adhesive behaviors was fabricated. The as-prepared surface is covered by porous PVDF spheres. The combination of hydrophobicity of PVDF and hierarchical roughness resulted from porous spheres contributing to the high contact angle and low sliding angle, corresponding to Cassie state and lotus leaves effect. Upon uniaxial or biaxial tension, the distance among hydrophobic spheres is so high that more and more hydrophilic defects (PLLA film) have been exposed to water droplets, accounting for the quasi-superhydrophobic surface with a higher sliding angle. This is the reason for the Wenzel state and rose petals effect. After heating, PLLA film recovers to its original state. The porous PVDF spheres cover the whole film again, leading to the enhanced mobility of water droplets on the surface. The transition between the rose petals effect and the lotus leaves effect is programmable and reversible. Our result provides a novel strategy to tailor adhesive behaviors by combining (quasi-)superhydrophobic surface with shape memory effect.

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“…Hence, the pore size of the separation material must be lower than the droplet size. Therefore, there is a trade‐off between the separation speed and accuracy of 2D superwetting separation materials 19 . Thereby, it has been challenging to develop 2D superwetting separation materials with high flux and precision.…”

Section: Introductionmentioning

confidence: 99%

Robust graphene/poly(vinyl alcohol) aerogel for high‐flux and high‐purity separation of water‐in‐oil emulsion and its computational fluid dynamic simulation

et al. 2022

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Due to the trade‐off between purity and flux, the development of high‐purity, high‐flux oil–water separation materials is still an arduous challenge. Herein, to achieve emulsion separation with high purity and high permeability, fluorinated graphene/poly(vinyl alcohol) aerogel (FGPA) with strong honeycomb was obtained via a facile freeze‐drying method, and the separation mechanism was investigated via computational fluid dynamics (CFDs) simulation. The as‐prepared FGPA exhibited superhydrophobicity‐superoleophobicity and cyclic compression stability. Under the complex pore and superhydrophobicity, FGPA could separate water‐in‐oil emulsions with droplet sizes several times smaller than their own aperture only under gravity with ultrahigh flux (3255 L m−2 h−1) and ultrahigh purity (99.9%). Also, the separation process as visualized using simulations revealed that the vortex accelerates the demulsification behavior and promotes the gathering of water droplets rebounding on the superhydrophobic surface, so that the water droplets are intercepted. Therefore, FGPA has broad practical application potential in high‐flux and high‐purity oil–water emulsion separation.

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Hierarchically porous membranes with isolated-round-pores connected by narrow-nanopores: A novel solution for trade-off effect in separation

Cited by 29 publications

References 39 publications

Inclusion/Exclusion Behaviors of Small Molecules during Crystallization of Polymers in Miscible PLLA/TAIC Blend

Inclusion/Exclusion Behaviors of Small Molecules during Crystallization of Polymers in Miscible PLLA/TAIC Blend

Programmable Transition between Adhesive/Anti-Adhesive Performances on Porous PVDF Spheres Supported by Shape Memory PLLA

Robust graphene/poly(vinyl alcohol) aerogel for high‐flux and high‐purity separation of water‐in‐oil emulsion and its computational fluid dynamic simulation

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