Phase-specific pore growth in ultrathin bicomponent films from cellulose-based polysaccharides

Taajamaa, Laura; Rojas, Orlando J.; Laine, Janne

doi:10.1039/c1sm06020a

Cited by 13 publications

(26 citation statements)

References 49 publications

(78 reference statements)

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“…With the evaporation of more solvent from the film, the upper layer of the film gets unstable with the formation of holes. The latter is then filled with the lower (liquid phase) layer as it is shown for ALG-CMC coated (first) layer (Figure S1) (Taajamaa et al, 2011). Interestingly, the phase separation is retained even after the third layer (Figure 1, top row and Figure S2).…”

Section: Resultsmentioning

confidence: 84%

“…The segregate phase separation is well-known for water soluble polymers (e.g., proteins- polysaccharides) for several years (Doublier et al, 2000), but not reported for spin-coated blend films. Keeping this mind, we believe that the lateral phase separation that occurred in the case of ALG-CMC blend, which stays in one phase in water, is of the segregate type, which can be explained by the transient bilayer theory (Heriot and Jones, 2005; Taajamaa et al, 2011).…”

Section: Resultsmentioning

confidence: 95%

“…The reports on the phase separation of polymer blends from (organo-soluble) hydrophobic polymers upon spin-coating are manifold (Taajamaa et al, 2011; Strasser et al, 2016). Whereas, no studies on the formation of blend surfaces from spin-coated polysaccharides, which are hydrophilic and water-soluble, can be found to the best of our knowledge.…”

Section: Resultsmentioning

confidence: 99%

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Polysaccharide Thin Solid Films for Analgesic Drug Delivery and Growth of Human Skin Cells

et al. 2019

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Chronic wounds not only lower the quality of patient's life significantly, but also present a huge financial burden for the healthcare systems around the world. Treatment of larger wounds often requires the use of more complex materials, which can ensure a successful renewal or replacement of damaged or destroyed tissues. Despite a range of advanced wound dressings that can facilitate wound healing, there are still no clinically used dressings for effective local pain management. Herein, alginate (ALG) and carboxymethyl cellulose (CMC), two of the most commonly used materials in the field of chronic wound care, and combination of ALG-CMC were used to create a model wound dressing system in the form of multi-layered thin solid films using the spin-assisted layer-by-layer (LBL) coating technique. The latter multi-layer system was used to incorporate and study the release kinetics of analgesic drugs such as diclofenac and lidocaine at physiological conditions. The wettability, morphology, physicochemical and surface properties of the coated films were evaluated using different surface sensitive analytical tools. The influence of in situ incorporated drug molecules on the surface properties (e.g., roughness) and on the proliferation of human skin cells (keratinocytes and skin fibroblasts) was further evaluated. The results obtained from this preliminary study should be considered as the basis for the development “real” wound dressing materials and for 3D bio-printing applications.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 95%

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Polysaccharide Thin Solid Films for Analgesic Drug Delivery and Growth of Human Skin Cells

et al. 2019

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“…While CTA membranes prepared by the phase inversion technique do not have the ideal permeability for post combustion capture, their high CO 2 /N 2 selectivity, commercial readiness and proven industrial resilience means that they could have strong potential. Thin film composite CTA membranes have been prepared by other workers [8][9][10] and emerging membrane fabrication technologies such as layer by layer [11] and continuous assembly of polymers (CAP) [12] approaches could allow the thickness of the active layer to be reduced further, which would result in adequate permeance to meet gas flux requirements. Alternatively, the use of porous additives within the active layer to form a mixed matrix structure could also improve the permeability of the structure, without compromising the selectivity [13].…”

Section: Introductionmentioning

confidence: 99%

The potential for use of cellulose triacetate membranes in post combustion capture

Kanehashi

Scholes

et al. 2016

International Journal of Greenhouse Gas Control

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Cellulose triacetate (CTA) membranes occupy much of the gas separation market in natural gas processing. With a high CO 2 /N 2 selectivity, this material may also be prospective for post-combustion carbon capture, if the permeance can be optimised. In capture applications, the impacts of liquid water condensate of variable pH, SO x and NO x on the gas separation performance are of critical interest to ensure maximum membrane lifetime. In this work, dense CTA membranes were aged in pH solutions of 3, 7 and 13 for a total of 60 days. It was found that the plasticisation of the CTA membrane when aged in pH 3 and pH 7 solutions enhanced the permeability of CO 2 and N 2 by over 30% with little impact on CO 2 /N 2 selectivity. Conversely, the membrane aged at pH 13 failed due to hydrolysis reactions. The membrane was selective for SO 2 over CO 2 with a SO 2 permeability of 20 Barrer. Conversely, NO did not readily permeate, so that the permeate composition was below the level of detection. CTA membranes stored in SO 2 /N 2 and pure N 2 for a 120 day period at 22 o C were relatively stable, with a slight loss in permeability due to membrane aging. Conversely, a significant loss in permeability was observed when these membranes were exposed to 0.74 kPa of NO for the same period. The performance loss appeared to relate to reaction of alcohol groups within the cellulose acetate structure with trace levels of NO 2 in the gas mixture. The results highlight the possibility for use of CTA membranes in postcombustion capture, if the active layer thickness can be reduced to enhance gas flux.

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“…Only the parts of the TMSC coating which are not covered by the mask are regenerated to pure cellulose. Already known structuring methods for cellulose thin films allowed the manufacturing of hydrophilic/hydrophobic domains from TMSC and other hydrophobic cellulose derivatives by a phase separation process 30. Nevertheless the method described in the present work allows controlling the geometry of the obtained features very selectively by applying a defined mask.…”

Section: Resultsmentioning

confidence: 99%

Functional Patterning of Biopolymer Thin Films Using Enzymes and Lithographic Methods

Kargl

Mohan

Köstler

et al. 2012

Adv Funct Materials

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Two different lithographic techniques for the patterning of thin biopolymer films are developed. The first method is based on using a microstructured elastomeric mold for the structuring of thin films of regenerated cellulose. The thin films are manufactured by spin‐coating of trimethylsilyl cellulose (TMSC) and subsequent regeneration. The microchannels formed by the mold and the cellulose film are filled with a cellulase solution by capillary action. In the areas exposed to the enzyme solution, the cellulose film is digested, whereas the area in contact with the mold is protected from the enzymatic activity. Optical thickness measurements, atomic force microscopy and fluorescent staining confirm a successful patterning of cellulose on several substrates by this method. The second method is based on the structured regeneration of thin TMSC films. TMSC surfaces are protected with metal masks and exposed to vapors of hydrochloric acid. These treatments result in hydrophilic cellulose structures surrounded by hydrophobic TMSC with differing physicochemical properties. Treatments of the obtained structures with cellulases allow the selective removal of pure cellulose, whereas a TMSC pattern remains on the surface. These TMSC can be regenerated back to pure cellulose by treatments with vapors of hydrochloric acid. The developed methods allow the effective fabrication of micropatterned biopolymer thin films suitable for further functionalization and application in, e.g., bioanalytical devices. This is shown by the immobilization and detection of single‐stranded DNA on structured cellulose surfaces. Owing to the versatility of both patterning approaches the methods can be further extended to other combinations of substrates and enzymes.

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Phase-specific pore growth in ultrathin bicomponent films from cellulose-based polysaccharides

Cited by 13 publications

References 49 publications

Polysaccharide Thin Solid Films for Analgesic Drug Delivery and Growth of Human Skin Cells

Polysaccharide Thin Solid Films for Analgesic Drug Delivery and Growth of Human Skin Cells

The potential for use of cellulose triacetate membranes in post combustion capture

Functional Patterning of Biopolymer Thin Films Using Enzymes and Lithographic Methods

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