Low moisture permeation measurement through polymer substrates for organic light emitting devices

Kumar, Rajesh; Auch, Mark Dai Joong; Ou, Eric C.-W.; Guenther, Ewald; Chen, Jin

doi:10.1016/s0040-6090(02)00584-9

Cited by 94 publications

(62 citation statements)

References 2 publications

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“…[1,2] Prevailing technologies, such as SiO x and Al x O y thin films, provide a relatively impermeable layer to oxygen, but tend to have poor adhesion, flexibility, and require costly vacuum-based processing. [3,4] (2 of 5) 1600594 using formed or wired grooves to deposit a specific wet film thickness.…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films

Haile

Sarwar

Henderson

et al. 2016

Macromol. Rapid Commun.

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Multilayer films deposited from water using layer-by-layer (LbL) assembly have shown extraordinarily low oxygen permeability and are of high interest due to their robustness, tailorability, and ease of fabrication. [5][6][7][8][9] Despite all the advantages associated with LbL assembly, the large number of processing steps remains a considerable challenge for commercial use. [10,11] In order to apply films composed of oppositely charged polyelectrolytes to substrates using just one or two deposition steps, solutions containing polyelectrolyte complexes (PECs) can be employed. [12][13][14][15] PECs are formed by the entropy-driven association of oppositely charged polyelectrolytes in water and can exist as stable colloids, flocculants, or metastable coacervates. [16][17][18][19][20] Governed by conditions such as pH and ionic strength, PEC coacervation is marked by a liquid-liquid phase separation, where a polymer rich coacervate phase is in equilibrium with a polymer poor solution phase. PEC coacervates are composed of weakly bound polyelectrolytes, and have viscous liquid-like behavior that can be exploited to quickly apply them as thin films. [18,[21][22][23][24] In the present study, polyelectrolyte coacervates were applied to substrates using Meyer rod coating (a common type of blade coating), [25] in an effort to quickly fabricate thin oxygen barrier films in a single step. The Meyer rod is drawn across a substrate, doctoring off coating fluid, Multilayer coatings consisting of oppositely charged polyelectrolytes have proven to be extraordinarily effective oxygen barriers but require many processing steps to fabricate. In an effort to prepare high oxygen barrier thin films more quickly, a polyelectrolyte complex coacervate composed of polyethylenimine and polyacrylic acid is prepared. The coacervate fluid is applied as a thin film using a rod coating process. With humidity and thermal posttreatment, a 2 µm thin film reduces the oxygen transmission rate of 0.127 mm poly(ethylene terephthalate) by two orders of magnitude, rivalling conventional oxygen barrier technologies. These films are fabricated in ambient conditions using low-cost, water-based solutions, providing a tremendous opportunity for single-step deposition of polymeric high barrier thin films.

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Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films

Haile

Sarwar

Henderson

et al. 2016

Macromol. Rapid Commun.

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“…23 The activation energy, 30 kJ mol Ϫ1 , for white samples is higher for a physical process obeying Henry's law, although activation energy reported for processes such as diffusion 31 and permeation of water 32 in and through the polymer are ϳ 36 kJ mol…”

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confidence: 98%

Effect of moisture‐ingress on adhesion energy in a metal oxide‐polymer system

Devasahayam

2005

J of Applied Polymer Sci

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This work quantifies the damage caused by moisture in a metal coating system under extreme weathering conditions, using Variable Radius Roll Adhesion Test (VaRRAT). Interfacial toughness (adhesion energy) between the metal oxide and the polymer in painted steel panels, studied by using VaRRAT, is observed to fall with increasing temperature and time of exposure to moisture. Possible cause for irreversible loss in adhesion energy in the paint system is attributed to the sorption of free water at the metal oxide-polymer interface. Different failure responses were observed in two different paint-metal systems. Adsorption or diffusion in the Henry's mode is rate controlling in green paints as indicated by the low activation energy of 12 kJ mol Ϫ1 . The white samples showed a high activation energy of 30 kJ mol Ϫ1 , indicating a mixed process of diffusion as well as chemical to be rate determining. Different paint/ binder ratios are responsible for the different responses of these samples.

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“…[19]. However, the low flexibility of inorganic films can diffuse moisture and/or oxygen in atmosphere through the cracks or pinholes [8]. Also, the cracks were main cause of degradation in flexible devices.…”

Section: Resultsmentioning

confidence: 99%

“…However, there is a limit to various deposition process and flexibility. The low flexibility of inorganic films can diffuse moisture and/or oxygen in atmosphere through the micro cracks or pinholes [8,9]. On the other hand, plasma polymerized thin films deposited by plasma enhanced chemical vapor deposition (PECVD) at 25 • C have the characteristics such as high transmittance as a function of deposition condition, pinhole-free, and high flexibility [10].…”

Section: Introductionmentioning

confidence: 99%