Study on the preparation and performance of low gas permeability trifluoropropyl phenyl silicone rubber

Zhu, Hua; Dai, Zhangjun; Wei-ping, TU

doi:10.1039/c7ra07195g

Cited by 9 publications

(7 citation statements)

References 19 publications

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“…Therefore, acceptable sulfurization resistance could be obtained. Notably, after the LEDs were exposed to sulfur gas for 24 h, those encapsulated with samples 3 and 4 exhibited higher flux retention than that encapsulated with only trifluoropropyl phenyl silicone rubber or even with an additional protective polysilazane top layer [21]. The much longer duration time of approximately 240 h provided strong evidence of the durability of the present siloxane-modified epoxy recipe.…”

Section: Sulfurization Resistance Of the Transparent Siloxane-modifiementioning

confidence: 82%

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Novel Siloxane-Modified Epoxy Resins as Promising Encapsulant for LEDs

et al. 2019

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This study investigated a new category of transparent encapsulant materials for light-emitting diodes (LEDs). It comprised a phenyl group that contained siloxane-modified epoxy (SEP-Ph) hybridized with a cyclic tetrafunctional siloxane-modified epoxy (SEP-D4) with methylhexahydrophthalic anhydride (MHHPA) as a curing agent. The SEP-Ph/SEP-D4 = 0.5/0.5 (sample 3) and SEP-D4 (sample 4) could provide notably high optical transmittance (over 90% in the visible region), high-temperature discoloration resistance, low stress, and more crucially, noteworthy sulfurization resistance. The lumen flux retention of the SEP encapsulated surface mounted device LEDs remained between approximately 97% and 99% after a sulfurization test for 240 h. The obtained comprehensive optical, mechanical, and sulfurization resistance proved the validity and uniqueness of the present design concept with complementary physical and chemical characteristics.Polymers 2020, 12, 21 2 of 11 of anhydride hardener and accelerator [14,15]. Huang et al. developed a series of cyclic silicone epoxies with various numbers of epoxy groups. By curing with aluminum acetylacetonate (Al(acac) 3 ) and diphenylsilanediol (Ph 2 Si(OH) 2 ), enhanced ultraviolet stability was achieved compared with an anhydride-cured cycloaliphatic epoxy [16]. Hue et al. prepared a transparent composition using the diglycidyl ether of bisphenol A and a phenylmethylsiloxane-modified epoxy (PMSE) hybrid resin. Curing with methylhexahydrophthalic anhydride (MHHPA) revealed that the addition of an appropriate amount of PMSE could effectively improve high-temperature thermal stability, dynamic mechanical stability, and performance of LEDs [18].Currently, surface mounted device LEDs (SMD LEDs) are advancing and their packages are becoming smaller and thinner. This allows harmful contaminants in the atmosphere such as hydrogen sulfide (H 2 S) to easily permeate an LED's package through its transparent encapsulation material.In this case, the bottom silver electrodes would darken because of the formation of silver sulfide, which would be accompanied by a significant decrease in the LED's light output. Although transparent epoxy-based encapsulants exhibit suitable gas barrier properties, the high thermal stress of epoxy resins that is generated during the soldering or temperature-cycling process would cause catastrophic damage. By contrast, silicone materials possess relatively low thermal stress compared with conventional epoxy resins, but their higher gas permeation properties would pose a problem for thin SMD LED packages, especially in outdoor applications.Many research studies have been conducted to enhance the gas barrier properties of transparent polymers, one of which added nanoscale lamellar fillers with a large aspect ratio, such as clay or graphene, into the polymer matrix [19,20]. The addition of clay can alter and extend the gas molecule diffusion pathway; furthermore, the incorporation of graphene can effectively prevent gas molecules from permeating into the polymer matrix; ho...

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Section: Sulfurization Resistance Of the Transparent Siloxane-modifiementioning

confidence: 82%

“…The second option is to employ vapor deposition or coat a dense inorganic or organic material (e.g., SiOx, Al 2 O 3 , or organic polysilazane) onto the surface of the polymer matrix. However, this approach requires special facilities (e.g., CVD and vacuum conditions) and complicated processes [21][22][23].…”

mentioning

confidence: 99%

Novel Siloxane-Modified Epoxy Resins as Promising Encapsulant for LEDs

et al. 2019

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“…Upon infusion, the lubricant immediately spread across the samples and the surfaces regained transparency. This change was induced by the similar refractive indices of the PVDF-PMMA blend and PTFS oil1.44 and 1.43, respectively. Transparency indicated that a continuous layer had been formed between the substrate and the lubricant and that all of the air gaps present on the surface had been filled.…”

Section: Results and Discussionmentioning

confidence: 99%

Highly Stable Hierarchically Structured All-Polymeric Lubricant-Infused Films Prevent Thrombosis and Repel Multidrug-Resistant Pathogens

Afonso

Bayat

Ladouceur

et al. 2022

ACS Appl. Mater. Interfaces

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Thrombus formation and infections caused by bacterial adhesion are the most common causes of failure in blood-contacting medical devices. Reducing the interaction of pathogens using repellent surfaces has proven to be a successful strategy in preventing device failure. However, designing scale-up methodologies to create large-scale repellent surfaces remains challenging. To address this need, we have created an all-polymeric lubricant-infused system using an industrially viable swellingcoagulation solvent (S-C) method. This induces hierarchically structured micro/nano features onto the surface, enabling improved lubricant infusion. Poly(3,3,3-trifluoropropylmethylsiloxane) (PTFS) was used as the lubricant of choice, a previously unexplored omniphobic nonvolatile silicone oil. This resulted in allpolymeric liquid-infused surfaces that are transparent and flexible with long-term stability. Repellent properties have been demonstrated using human whole blood and methicillin-resistant Staphylococcus aureus (MRSA) bacteria matrices, with lubricated surfaces showing 93% reduction in blood stains and 96.7% reduction in bacterial adherence. The developed material has the potential to prevent blood and pathogenic contamination for a range biomedical devices within healthcare settings.

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“…One possible approach is use of fluoroelastomer that has low air permeability and high-temperature resistance [48]. Mixing nanoparticles in polymer materials [49] or surface coating with low permeability materials [50] could be an other alternative.…”

Section: Discussionmentioning

confidence: 99%

Pop-up cookie molds: self-folding elastomer sheets using thermal expansion of embedded air chambers

Kwon¹,

Park²,

Choi³

et al. 2021

Smart Mater. Struct.

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Self-folding is a promising concept in the fields of smart materials and robotics, which allows self-assembly and multi-functionality. Although there have been approaches to realize self-folding mechanisms using different techniques, and their practical applications are not sufficiently investigated. Here, we propose untethered, self-folding polymer structures with embedded air chambers, which easily transform two-dimensional flat shapes into preprogrammed three-dimensional (3D) shapes when heat energy is transferred into the structures resulting in thermal expansion of the air chambers. This mechanism is particularly useful for casting materials that require shape and phase changes simultaneously if the proposed structures are used as molds. As a practical application, we present pop-up cookie molds that can bake 3D-shaped cookies from flat cookie dough. Analytical modelings based on the ideal gas law, the principle of minimum potential energy, and the lumped capacitance method for heat transfer are established and experimentally validated using prototypes. These provide a prediction of the structure's bending curvature during the baking process. Furthermore, other target shapes, including bending, twisting, and their combinations, are also achieved by configuring various chamber designs. Finally, practical prototypes with more complex shapes are proposed, and their performances are demonstrated.

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Study on the preparation and performance of low gas permeability trifluoropropyl phenyl silicone rubber

Abstract: Low gas permeability coating can prevent oxygen and sulphur vapour from permeating into silicone rubber and protect electronic components, chips, electrodes, medicines, etc. from oxidation and sulfuration.

Cited by 9 publications

References 19 publications

Novel Siloxane-Modified Epoxy Resins as Promising Encapsulant for LEDs

Novel Siloxane-Modified Epoxy Resins as Promising Encapsulant for LEDs

Highly Stable Hierarchically Structured All-Polymeric Lubricant-Infused Films Prevent Thrombosis and Repel Multidrug-Resistant Pathogens

Pop-up cookie molds: self-folding elastomer sheets using thermal expansion of embedded air chambers

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