Engineering microfluidic papers: effect of fiber source and paper sheet properties on capillary-driven fluid flow

Böhm, Alexander; Carstens, Franz; Trieb, Christian; Schabel, Samuel; Biesalski, Markus

doi:10.1007/s10404-013-1324-4

Cited by 96 publications

(67 citation statements)

References 27 publications

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“…When this process starts, the wetting is thus governed by the capillary‐driven flow of the water into the paper substrate. This of course opens the opportunity to tune the wetting after the switching of the DASA since the flow rate, as reported by Böhm et al, in paper can be adjusted by alterations of the paper properties such as fiber length, pore size and porosity . The light‐switched coating containing 5 stays hydrophilic and discolored after several months under standard conditions (23 °C and 50% r.h.).…”

Section: Contact Angle Measurements Of Paper Substrates Coated With Cmentioning

confidence: 74%

Independent Two Way Switching of the Wetting Behavior of Cellulose‐Derived Nanoparticle Surface Coatings by Light and by Temperature

Nau

Seelinger

Biesalski

2019

Adv Materials Inter

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light-triggered changes in the polarity of a material are of interest, as the switching mechanism does not rely on diffusion, as is the case with the pH-or electrolyteinduced switching of polyelectrolytes. [18] However, one of the major challenges of light-responsive spiropyran that has yet to be solved is the rather slow dynamics of the molecular rearrangements (i.e., slow switching behavior) and the oxidative degradation that can occur during the process. Another group of photoresponsive polarity-switching materials are known as donor acceptor Stenhouse adducts (DASAs). DASAs were discovered recently and have gained an increasing amount of attention in a broad range of fields, generating literal toolboxes for the fast implementation into existing systems to add further functionalities. [19][20][21][22][23][24][25][26][27] These compounds are derived from furfural, a commodity chemical and plant by-product, which is a great step toward sustainable building blocks for photoswitchable compounds. Initial studies focusing on the incorporation of the photoresponsive DASA domain into polymer matrices have been carried out, and the products of which displayed a photoinduced change in wetting behavior based around the mechanism displayed in Figure 1a. [28,29] Both studies found that there was no observable back-switching for DASAs on surfaces, which stands in sharp contrast to the fast switching observed for these molecules in solution. A newer study has reported that second-generation DASA-containing polymers could be switched back within hours, triggered by the glass transition of the matrix polymer. [30] Very recently Zheng et al. reported the reversible switching of a silica nanoparticle bound poly dopamine based DASA system, which could, once immobilized on a polydimethylsiloxane substrate, induce a change in water contact angle (WCA) of up to ≈40°. [31] We have been working in the recent past on cellulose-ester and hydroxypropyl cellulose (HPC)-ester polymers, which can be tailored with respect to their thermal behavior (T g ), and such materials can be applied as nanoparticle coatings on planar surfaces. [32,33] When cellulose-or HPC-ester nanoparticles are being coated onto a planar solid or porous (e.g., paper) substrate, superhydrophobic surface properties with WCAs exceeding 150° can be observed through a combination of roughness (a film consisting of nanoparticles) and low surface energy. Through thermal treatment, the nanoparticle structure Recently, donor acceptor Stenhouse adducts (DASAs) have received interest as photoresponsive polarity switches. In this work, a range of DASAs are synthesized and combined with nanoparticles from hydroxypropyl cellulose stearic acid ester to yield a photoresponsive composite material. This composite is spray-coated onto porous paper substrates, forming an interface that is initially superhydrophobic and can be switched by a visible light trigger to become hydrophilic. Subsequently, this hydrophilic state can be switched back to regain a hydrophobic surface by heating abo...

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Section: Contact Angle Measurements Of Paper Substrates Coated With Cmentioning

confidence: 74%

Independent Two Way Switching of the Wetting Behavior of Cellulose‐Derived Nanoparticle Surface Coatings by Light and by Temperature

Nau

Seelinger

Biesalski

2019

Adv Materials Inter

Self Cite

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“…In what follows we discuss the problems associated to the prescription of flow rates Q(l), on the base of eqn. (10). The first aspect to be noted is that, in contrast to the case of ‫)݈(ݒ‬ = ‫,)݈(ܣ/)݈(ܳ‬ flow rates Q(l) are restricted to monotonically decreasing functions (for increasing Q(l), eqn.…”

Section: Resultsmentioning

confidence: 99%

“…(10). Thus, after calculations and reordering, one obtains the crosssectional profile ‫)ݔ(ܣ‬in terms of the desired velocity function ‫,)ݔ(ݒ‬…”

Section: Inverse Calculationmentioning

confidence: 99%

Rational design of capillary-driven flows for paper-based microfluidics

2015

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The design of paper-based assays that integrate passive pumping requires a precise programming of the fluid transport, which has to be encoded in the geometrical shape of the substrate. This requirement becomes critical in multiple-step processes, where fluid handling must be accurate and reproducible for each operation. The present work theoretically investigates the capillary imbibition in paper-like substrates to better understand fluid transport in terms of the macroscopic geometry of the flow domain. A fluid dynamic model was derived for homogeneous porous substrates with arbitrary cross-sectional shapes, which allows one to determine the cross-sectional profile required for a prescribed fluid velocity or mass transport rate. An extension of the model to slit microchannels is also demonstrated. Calculations were validated by experiments with prototypes fabricated in our lab. The proposed method constitutes a valuable tool for the rational design of paper-based assays.

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“…As mentioned above, there is a growing need for highly efficient continuous‐flow nanocatalysis with an excellent recycling system for truly green sustainable chemistry. To achieve this challenge, paper, which has been used traditionally on a daily basis, is expected to offer great potential for use as an efficient and recyclable flow reactor, because it has highly porous structures, a high absorption capacity for liquids, high stability in most solvents, is both hydrophilic and lipophilic nature, and is recyclable . Paper is composed of wood pulp fibers several tens of μm in width, which are derived from wood cells.…”

Section: Figurementioning

confidence: 99%

Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for Continuous‐Flow Nanocatalysis

et al. 2017

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Continuous‐flow nanocatalysis based on metal nanoparticle catalyst‐anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal nanoparticle‐anchored flow reactors to create more efficient and sustainable catalytic processes. In this study, traditional paper is used for a highly efficient, recyclable, and even renewable flow reactor by tailoring the ultrastructures of wood pulp. The “paper reactor” offers hierarchically interconnected micro‐ and nanoscale pores, which can act as convective‐flow and rapid‐diffusion channels, respectively, for efficient access of reactants to metal nanoparticle catalysts. In continuous‐flow, aqueous, room‐temperature catalytic reduction of 4‐nitrophenol to 4‐aminophenol, a gold nanoparticle (AuNP)‐anchored paper reactor with hierarchical micro/nanopores provided higher reaction efficiency than state‐of‐the‐art AuNP‐anchored flow reactors. Inspired by traditional paper materials, successful recycling and renewal of AuNP‐anchored paper reactors were also demonstrated while high reaction efficiency was maintained.

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Engineering microfluidic papers: effect of fiber source and paper sheet properties on capillary-driven fluid flow

Cited by 96 publications

References 27 publications

Independent Two Way Switching of the Wetting Behavior of Cellulose‐Derived Nanoparticle Surface Coatings by Light and by Temperature

Independent Two Way Switching of the Wetting Behavior of Cellulose‐Derived Nanoparticle Surface Coatings by Light and by Temperature

Rational design of capillary-driven flows for paper-based microfluidics

Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for Continuous‐Flow Nanocatalysis

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