Structure and barrier property of acrylatemethacrylate film coating in aspirin microcapsules

Eichie, FE; Okor, R. S.; Gröning, R.

doi:10.1002/app.22176

Cited by 7 publications

(5 citation statements)

References 15 publications

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“…Materials. Polyvinylpyrrolidone (PVP) (M w = 360,000 g/mol), with a density of 1.2 g/cm 3 , was purchased from Sigma-Aldrich (Milwaukee, WI) and used as received. Natural sodium montmorillonite (MMT) clay was provided by Southern Clay Products, Inc. (Gonzales, TX) and used as received.…”

Section: Methodsmentioning

confidence: 99%

“…Natural sodium montmorillonite (MMT) clay was provided by Southern Clay Products, Inc. (Gonzales, TX) and used as received. MMT platelets have a negative surface charge in deionized water, a reported density of 2.86 g/cm 3 , thickness of 1 nm, and an aspect ratio (l/d) of approximately 100− 1000. 42,43 Poly(ethylene terephthalate) (PET) film (trade name ST505 by DuPont-Teijin Films), with a thickness of 179 μm, was purchased from Tekra (New Berlin, WI) and used as the substrate for OTR testing and transmission electron microscopy (TEM).…”

Section: Methodsmentioning

confidence: 99%

“…Flexible, transparent gas barrier layers are necessary for the advancement of flexible displays, along with improving food and pharmaceutical packaging. − Inorganic metal-oxide layers, such as SiO x , exhibit the lowest gas transmission rates and highest transparency among commercially available barriers. Despite having excellent as-deposited barriers, these thin films are prone to cracking when flexed and require complex fabrication when layered with polymers to improve barrier and flexibility. ,− Flexible polymer–clay composites have been shown to modestly improve the barrier over the neat polymer matrix but exhibit low optical clarity and relatively high gas transmission rates. ,, By using layer-by-layer assembly, polymer–clay thin films have been shown to exhibit high gas barrier, rivaling that of thin metal oxides, while maintaining the mechanical properties of a traditional polymer composite. − The best of these films is 50 nm thick and exhibits an oxygen transmission rate of 0.005 cc/m 2 ·day due to high clay concentration (∼37 wt %) and near complete exfoliation of platelets oriented parallel to the substrate’s surface .…”

Section: Introductionmentioning

confidence: 99%

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Humidity-Responsive Gas Barrier of Hydrogen-Bonded Polymer–Clay Multilayer Thin Films

et al. 2012

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It is well-known that gas barrier behavior in most polymer and composite materials degrades at elevated humidity. In an effort to reduce this trend, the influence of relative humidity (RH) on the gas barrier of thin films comprising montmorillonite clay and polyvinylpyrrolidone, created via layer-by-layer assembly, was investigated. These hydrogen-bonded thin films approximately doubled in thickness when RH was increased to 100% but returned to within 1% of the original thickness when RH was decreased to 0%, with minimal swelling/deswelling hysteresis. Transmission electron microscopy reveals a highly aligned nanobrick wall structure, which has a clay concentration of 74 wt % and greater than 95% visible light transmission. The oxygen transmission rate (OTR) through these films, deposited on 179 μm poly(ethylene terephthalate) film, remarkably decreases as a function of RH. A 40-BL film has an OTR of 3.9 (cc/(m2·day·atm)) at 0% RH, while exposure to 100% RH decreased this value by 11%. In this case, greater spacing between clay layers and maintenance of tight packing within the layers (due to relatively weak H-bonding between polymer and clay) combine to create a more tortuous path at high humidity. This study marks the first polymer–clay assembly that exhibits improved gas barrier at high humidity, which is important for various packaging applications (e.g., food and flexible electronics).

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Humidity-Responsive Gas Barrier of Hydrogen-Bonded Polymer–Clay Multilayer Thin Films

et al. 2012

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“…Transparent and flexible gas barrier films are a key component for flexible electronics and pharmaceutical and food packaging . Films exhibiting the lowest gas transmission rates typically contain inorganic oxide layers (e.g., SiO x or Al 2 O 3 ) – , which are prone to cracking when flexed .…”

Section: Introductionmentioning

confidence: 99%

Transparent Clay−Polymer Nano Brick Wall Assemblies with Tailorable Oxygen Barrier

Priolo

Gamboa

Grunlan

2009

ACS Appl. Mater. Interfaces

218

262

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Thin films of sodium montmorillonite clay and branched polyethylenimine (PEI) are deposited on various substrates using layer-by-layer assembly. Films with 40 polymer-clay layers contain more than 84 wt% clay, have hardness as high as 1 GPa, and are completely transparent. Oxygen transmission rates (OTR) through these films decrease as the pH of PEI increases. These pH-tailorable properties are the result of changing PEI charge density, which causes the polymer to deposit more thickly at high pH because of low charge density. After 70 PEI (at pH 10)-clay layers are deposited onto 179 µm poly(ethylene terephthalate) film, the resulting 231 nm assembly has an OTR below the detection limit of commercial instrumentation (<0.005 cc/(m 2 day atm)). When multiplied by thickness, the resulting oxygen permeability is found to be less than 0.002 × 10 -6 cc/(m day atm)), which is lower than values typically reported for SiOx. This is the lowest permeability ever reported for a polymer-clay composite and is believed to be due to a brick wall nanostructure created by the alternate adsorption of polymeric mortar and highly oriented, exfoliated clay platelets. Because of their high level of transparency and gas barrier, these films are good candidates for a variety of flexible electronics, food, and pharmaceutical packaging.

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“…Flexible, transparent layers with a high barrier to atmospheric gases (e.g., oxygen and moisture vapor) are a key component for flexible electronics, food, and pharmaceutical packaging. − Monolithic, inorganic oxide layers, such as SiO x or Al x O y , have been extensively investigated for their high barrier performance and optical clarity at thicknesses typically below 100 nm, − but these films are prone to defect formation during deposition, poor substrate adhesion, and failure upon flexure at strains less than 2%. − Additionally, the best inorganic oxides generally require extreme processing conditions (e.g., plasma-enhanced chemical vapor deposition) and suffer from low productivity and high costs when layered with polymers. , Clay-filled polymer composites have been shown to improve barrier over neat polymer films, − but exhibit lower transparency and oxygen barrier relative to the aforementioned metal-oxide layers. , A relatively new technique, layer-by-layer (LbL) assembly, has been shown to generate polymer–clay thin films that exhibit extremely low oxygen transmission rates, high transparency in the visible light spectrum, and tunable gas barrier behavior. − …”

Section: Introductionmentioning

confidence: 99%

Precisely Tuning the Clay Spacing in Nanobrick Wall Gas Barrier Thin Films

et al. 2013

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The influence of clay-layer spacing on gas barrier thin films of sodium montmorillonite clay and polyelectrolytes, created via layer-by-layer assembly, is investigated. The alternate deposition of polymers and clay leads to the assembly of a nanobrick wall structure that is highly impermeable to gases. In an effort to tailor the thickness (or spacing) between clay layers, films with differing numbers of polymer layers between clay depositions were examined. Films analyzed for their thickness, clay concentration, transparency, nanostructure, and oxygen barrier as a function of layers (or spacing) between clay depositions reveal linear growth, optical clarity, and low OTR at 100 nm thick and containing only four clay layers. An optimal thickness between clay layers appears to exist for achieving the highest oxygen barrier LbL films (PO2 < 1 × 10–21 cc(STP)·cm/(cm2·s·Pa)). This knowledge can ultimately minimize deposition steps and lead to decreased thin film fabrication times.

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Structure and barrier property of acrylatemethacrylate film coating in aspirin microcapsules

Cited by 7 publications

References 15 publications

Humidity-Responsive Gas Barrier of Hydrogen-Bonded Polymer–Clay Multilayer Thin Films

Humidity-Responsive Gas Barrier of Hydrogen-Bonded Polymer–Clay Multilayer Thin Films

Transparent Clay−Polymer Nano Brick Wall Assemblies with Tailorable Oxygen Barrier

Precisely Tuning the Clay Spacing in Nanobrick Wall Gas Barrier Thin Films

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