Stimuli-responsive membranes

Wandera, Daniel; Wickramasinghe, S. Ranil; Husson, Scott M.

doi:10.1016/j.memsci.2010.03.046

Cited by 395 publications

(282 citation statements)

References 160 publications

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“…Stimuli-responsive membranes change their physical properties in response to changes in environmental conditions, such as pH, solution ionic strength, temperature, concentration of specific chemical species, electric and magnetic field [1][2][3]. Changes in the physical properties of the membrane in response to changed environmental conditions can lead to changes in the mass transfer and interfacial properties of the membrane.…”

Section: Introductionmentioning

confidence: 99%

“…Among the stimuli that can be used to control the response of the system, temperature and pH-responsive factors have drawn much attention. In general, responsive membranes are formed from stimuli-sensitive materials (polymers or copolymers) or by modification of existing membranes by various chemical/physical processes to incorporate stimuli-responsive polymers [1,2]. An example of a pH-sensitive polymer is the natural polymer chitosan.…”

Section: Introductionmentioning

confidence: 99%

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pH-responsive hydrogel membranes based on modified chitosan: water transport and kinetics of swelling

2015

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pH-responsive membranes prepared by treating chitosan (Ch) with glutaraldehyde (GA) or with GA and sulfuric acid (SA) were studied. The structure and properties of the membranes were characterized by Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis. The effect of the cross-linking process both on the dynamic swelling behaviour of the hydrogel membranes and on the mechanism of water transport through those membranes was investigated in buffer solutions of different pH (1.2-9.5). The mechanism of water transport through the hydrogel chitosan membranes was affected by membrane composition and pH of the swelling medium. Non-cross-linked Ch membrane showed a non-Fickian swelling behaviour in the pH range 6.5-9.5. Chitosan membrane cross-linked with GA (Ch/GA) showed less-Fickian or Fickian swelling behaviour in all buffer solutions. In the case of chitosan membrane cross-linked with GA and SA (Ch/GA/SA), at low pH (lower than the pK a of the hydrogel) the water transport was controlled more by polymer relaxation than by penetrant diffusion. The experimental data clearly suggested that the swelling process in all buffer solutions obeyed second-order kinetics. Values of an apparent swelling rate constant for Ch/ GA and Ch/GA/SA membranes were of the same order of magnitude for acidic and neutral swelling media but they increased for alkaline solutions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

pH-responsive hydrogel membranes based on modified chitosan: water transport and kinetics of swelling

2015

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“…(Shacham et al, 1999) Alternative smart polymeric supports for separating and detecting biomolecules in microfluidic systems are stimuli-responsive membranes. (Xue et al, 2008;Wandera et al, 2010) They are characterized by pores that can open and close by electronic induced stimuli such as electric or magnetic fields. (Csetneki et al, 2006) Membranes incorporating specific recognition elements after detecting the presence of a specific substance or a specific stimulus were able to translate this signal into a change of physico-chemical properties (i.e., changes in the permeability).…”

Section: Immobilization Methodsmentioning

confidence: 99%

Smart Microfluidics: The Role of Stimuli- Responsive Polymers in Microfluidic Devices

Argentiere¹,

Gigli²,

Gerges³

et al. 2012

Advances in Microfluidics

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“…This resulted in a smaller hydrodynamic volume and therefore an apparent smaller molecular weight of the polymer itself was observed [17,[52][53][54]. Nevertheless, molar masses can easily be obtained and calculated by 1 H NMR spectroscopy and the results are additionally compiled in Table 2. It has to be mentioned, that a second less intensive distribution, which is shifted to higher molar masses, could be observed by SEC measurements.…”

Section: Functionalization Of Phema-containing Block Copolymers With mentioning

confidence: 99%

Ferrocene-Modified Block Copolymers for the Preparation of Smart Porous Membranes

et al. 2017

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Abstract:The design of artificially generated channels featuring distinct remote-switchable functionalities is of critical importance for separation, transport control, and water filtration applications. Here, we focus on the preparation of block copolymers (BCPs) consisting of polystyrene-block-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) having molar masses in the range of 91 to 124 kg mol −1 with a PHEMA content of 13 to 21 mol %. The BCPs can be conveniently functionalized with redox-active ferrocene moieties by a postmodification protocol for the hydrophilic PHEMA segments. Up to 66 mol % of the hydroxyl functionalities can be efficiently modified with the reversibly redox-responsive units. For the first time, the ferrocene-containing BCPs are shown to form nanoporous integral asymmetric membranes by self-assembly and application of the non-solvent-induced phase separation (SNIPS) process. Open porous structures are evidenced by scanning electron microscopy (SEM) and water flux measurements, while efficient redox-switching capabilities are investigated after chemical oxidation of the ferrocene moieties. As a result, the porous membranes reveal a tremendously increased polarity after oxidation as reflected by contact angle measurements. Additionally, the initial water flux of the ferrocene-containing membranes decreased after oxidizing the ferrocene moieties because of oxidation-induced pore swelling of the membrane.

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Stimuli-responsive membranes

Cited by 395 publications

References 160 publications

pH-responsive hydrogel membranes based on modified chitosan: water transport and kinetics of swelling

pH-responsive hydrogel membranes based on modified chitosan: water transport and kinetics of swelling

Smart Microfluidics: The Role of Stimuli- Responsive Polymers in Microfluidic Devices

Ferrocene-Modified Block Copolymers for the Preparation of Smart Porous Membranes

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