Parylene Layer Research Articles

Tailored micro-arc oxidation coatings to match with parylene for enhanced tribological performance of Ta-12W alloys

To improve the tribological properties of tantalum-tungsten alloys, dual-layer composite coatings are designed using micro-arc oxidation (MAO) and chemical vapor deposition (CVD) techniques. By adjusting the concentrations of NaOH and NaF additives as well as the oxidation mode (constant current/voltage) of MAO process, the microstructure and properties of underlying MAO layers are tailored for better matching with the top parylene layer, aiming to develop composite coatings capable of service under heavy loads. A comprehensive study is conducted to evaluate the effect of these parameters on the growth, microstructure, bond strength, and mechanical properties of MAO coatings, along with their subsequent impact on the friction and wear behavior under various loads for composite coatings. The findings reveal that increasing the concentration of either NaOH or NaF significantly increases the coating thickness, surface porosity, crystallinity, and hardness of MAO coatings, by promoting the spark discharge activities. However, distinct interfacial growth behavior is observed due to anionic effects caused by OH− and F−. The oxidation mode plays a crucial role in determining the mechanical quality of coatings; the constant voltage mode facilitates dense coatings with high adhesion due to its self-repairing mechanism. Furthermore, wear tests confirm that the enhanced mechanical properties and open-porosity of the MAO coatings markedly improve the tribological performance of composite coatings. This improvement is attributed to the excellent load-bearing capacity provided by hard MAO layers, as well as the anchoring and storage capabilities of the textural porous surfaces. The optimized composite coating demonstrates long-lasting low friction even under heavy loads up to 80 N.

A Wireless Battery-Free Implant With Optical Telemetry for In Vivo Cortical Stimulation.

We present a 100 μm-thick, wireless, and battery-free implant for brain stimulation through a U.S. Food and Drug Administration-approved collagen dura substitute without contact with the brain's surface, while providing visible-light spectrum telemetry to track the onset of stimulation. The device is fabricated on a 16 × 6.67 mm2 biocompatible parylene/PDMS substrate and is encapsulated with a 2 μm-thick transparent parylene layer that enables the relay of the LED brightness. The in vivo rodent testing confirmed the implant's ability to trigger motor response while generating observable brightness through the skin. The results reveal the prospect of wireless stimulation with enhanced safety by eliminating contact between the implant and the brain, with optical telemetry for facilitated tracking.

Highly Bright and Efficient Flexible Quantum Dot Light-Emitting Diodes on Metal-Coated PEN Substrate

Quantum-dot (QD) based light-emitting diodes (QLEDs) have attracted significant attention in state-of-the-art wearable displays owing to the high form factor of QDs with excellent optical/electrical properties. These advantageous properties have led to notable advancements in QLEDs technology, making them flexible, lightweight, and compatible with human skin, which meets the requirements of wearable applications. To make the QLEDs wearable, however, alleviating the heat generated under high current is an urgent challenge. In this study, we present a flexible and bright top-emissive QLED fabricated on a plastic substrate with a thin (200 nm) heat dissipation layer. To preserve QLED performance even under sweaty conditions, we employed double layers of Parylene C/SU-8 for substrate planarization and device encapsulation. Furthermore, compared with typical wearable substrates that can hardly dissipate heat, the Al-metal induced flexible substrate can effectively dissipate the generated heat even under high current densities (2.3 A/cm2), exhibiting a high luminance (∼366,000 cd/m2) and a current efficiency (43.3 cd/A), respectively. The delicate device design of flexible QLEDs is anticipated to contribute to the advancement of next-generation wearable optoelectronics.

Enhancing energy harvesting performance of bilayered parylene triboelectric nanogenerators through interfacial polarization

Self-powered multifunctional devices have found applications in various fields including internet of things, smart robotics, and wearable haptic technologies. Triboelectric Nanogenerators (TENGs) are particularly noteworthy as they operate based on simple triboelectrification between contacting materials, and provide significantly higher output performance compared to other energy harvesting devices. In this study, we introduce soft bilayer structured films to significantly enhance the interfacial polarization and the resulting triboelectric output performance. The soft bilayer film is composed of two layers: a layer of parylene derivatives with different functional groups and a composite layer of polydimethylsiloxane (PDMS) embedded with multi-wall carbon nanotube (MWCNT). The parylene-deposited MWCNT-PDMS films effectively induce interfacial polarization due to the difference in permittivity between the parylene derivatives and MWCNT-PDMS, resulting in substantial improvement in triboelectric performances. Moreover, the specific functional groups present in the parylene monomers significantly affect the triboelectric polarity of the parylene-deposited bilayer films. The bilayer films deposited with parylene including fluorine, methyl hydroxyl, and hydroxyl groups, which improve the electron-withdrawing capability, exhibit negative triboelectric properties. In contrast, the bilayer film deposited with parylene including methyl amine group, which enhances the electron-donating ability, exhibits a positive triboelectric property. Owing to the highly improved interfacial polarization in the parylene-deposited bilayer films, our TENG consisting of paired bilayer films demonstrates superior output performance (4.57 W/cm2 and 10.28 W/cm2 for contact and separation step, respectively) compared to devices based solely on single layers of parylene- or PDMS (less than a few of mW/cm2). Our approach to designing layer-structured dielectric films offers a simple yet effective method to significantly enhance the output performance of self-powered flexible devices through improved polarization.

Easy-To-Wear Auxetic SMA Knot-Architecture for Spatiotemporal and Multimodal Haptic Feedbacks.

Wearable haptic interfaces prioritize user comfort, but also value the ability to provide diverse feedback patterns for immersive interactions with the virtual or augmented reality. Here, to provide both comfort and diverse tactile feedback, an easy-to-wear and multimodal wearable haptic auxetic fabric (WHAF) is prepared by knotting shape-memory alloy wires into an auxetic-structured fabric. This unique meta-design allows the WHAF to completely expand and contract in 3D, providing superior size-fitting and shape-fitting capabilities. Additionally, a microscale thin layer of Parylene is coated on the surface to create electrically separated zones within the WHAF, featuring zone-specified actuation for conveying diverse spatiotemporal information to users with using the WHAF alone. Depending on the body part it is worn on, the WHAF conveys either cutaneous or kinesthetic feedback, thus, working as a multimodal wearable haptic interface. As a result, when worn on the forearm, the WHAF intuitively provides spatiotemporal information to users during hands-free navigation and teleoperation in virtual reality, and when worn on the elbow, the WHAF guides users to reach the desired elbow flexion, like a personal exercise advisor.

Ultra-thin parylene-aluminium hybrid coatings on nanocellulose films to resist water sensitivity

Non-sustainable single-use plastics used for food packaging needs to be phased out. Films made from cellulose nanofibrils (CNFs) are suitable candidates for biodegradable and recyclable packaging materials as they exhibit good mechanical properties, excellent oxygen barrier properties and high transparency. Yet, their poor water vapour barrier properties have been a major hindrance in their commercialisation. Here, we describe the preparation of 25 μm thick CNF films with significantly improved water vapour barrier properties after deposition of ultrathin polymeric and metallic coatings, parylene C and aluminium, respectively. When first adding a 40 nm aluminium layer followed by an 80 nm parylene layer, i.e. with a combined thickness of less than one percent of the CNF film, a water vapour transmission rate of 2.8 g m−2 d−1 was achieved at 38 °C and 90 % RH, surpassing a 25 μm polypropylene film (4–12 g m−2 d−1). This is an improvement of more than 700 times compared to uncoated CNF films, under some of the harshest possible conditions a packaging material will need to endure in commercial use. The layers showed a good and even coverage, as assessed by atomic force microscopy, and the parylene-coated surfaces were hydrophobic with a contact angle of 110°, providing good water repellency.

Characterization of thin film Parylene C device curvature and the formation of helices via thermoforming

In microfabricated biomedical devices, flexible, polymer substrates are becoming increasingly preferred over rigid, silicon substrates because of their ability to conform to biological tissue. Such devices, however, are fabricated in a planar configuration, which results in planar devices that do not closely match the shape of most tissues. Thermoforming, a process which can reshape thermoplastic polymers, can be used to transform flat, thin film, polymer devices with patterned metal features into complex three-dimensional (3D) geometries. This process extends the use of planar microfabrication to achieve 3D shapes which can more closely interface with the body. Common shapes include spheres, which can conform to the shape of the retina; cones, which can be used as a sheath to interface with an insertion stylet; and helices, which can be wrapped around nerves, blood vessels, muscle fibers, or be used as strain relief feature. This work characterizes the curvature of thin film Parylene C devices with patterned metal features built with varying Parylene thicknesses and processing conditions. Device curvature is caused by film stress in each Parylene and metal layer, which is characterized experimentally and by a mathematical model which estimates the effects of device geometry and processing on curvature. Using this characterization, an optimized process to thermoform thin film Parylene C devices with patterned metal features into 0.25 mm diameter helices while preventing cracking in the polymer and metal was developed.

Influence of Parylene F Coatings on the Wetting Properties of Soft Polydimethylsiloxane (PDMS)

Understanding the wettability of soft surfaces is of key importance for the development of protective and repellent coatings and controlling droplet dynamics when required. There are many factors that affect the wetting and dynamic dewetting behavior of soft surfaces, such as the formation of wetting ridges, the adaptive behavior of the surface caused by the interaction of the fluid with the surface, or the presence of free oligomers that are washed out of the soft surface. In this work, we report the fabrication and characterization of three soft polydimethylsiloxane (PDMS) surfaces with elastic moduli ranging from 7 kPa to 56 kPa. The dynamic dewetting behavior of liquids with different surface tensions was studied on these surfaces, and the data show soft and adaptive wetting behavior of the soft PDMS, as well as the presence of free oligomers. Thin layers of Parylene F (PF) were introduced to the surfaces and their influence on the wetting properties was studied. We show that the thin layers of PF prevent adaptive wetting by preventing the diffusion of liquids into the soft PDMS surfaces and by causing the loss of the soft wetting state. The dewetting properties of the soft PDMS are enhanced, leading to low sliding angles of ≤10° for water, ethylene glycol, and diiodomethane. Therefore, the introduction of a thin PF layer can be used to control wetting states and to increase the dewetting behavior of soft PDMS surfaces.

Bio-Inspired Micromachined Volumetric Flow Sensor with a Big Dynamic Range for Intravenous Systems.

Real-time monitoring of drug delivery in an intravenous infusion system can prevent injury caused by improper drug doses. As the medicine must be administered into the vein at different rates and doses in different people, an ideal intravenous infusion system requires both a low flow rate and large dynamic range monitoring. In this study, a bio-inspired and micromachined volumetric flow sensor is presented for the biomedical application of an intravenous system. This was realized by integrating two sensing units with different sensitivities on one silicon die to achieve a large dynamic range of the volumetric flow rate. The sensor was coated with a parylene layer for waterproofing and biocompatibility purposes. A new packaging scheme incorporating a silicon die into a flow channel was employed to demonstrate the working prototype. The test results indicate that the sensor can detect a volumetric flow rate as low as 2 mL/h, and its dynamic range is from 2 mL/h to 200 mL/h. The sensor performed better than the other two commercial sensors for low-flow detection. The high sensitivity, low cost, and small size of this flow sensor make it promising for intravenous applications.

Three-Degree-of-Freedom Electromagnetic Microactuator With Powder-Based Sm-Fe-N Magnets and Parylene Beams

In this paper, we report a moving magnet type electromagnetic actuator with three-degree-of-freedom, namely the displacement in XY axes and rotation around Z axis, by utilizing rare earth magnetic powder Sm-Fe-N. Parylene was utilized to fabricate springs to suspend four drive units and a center moving stage located in the four corners and the center of the actuator, respectively. The rare earth magnetic powder Sm-Fe-N with wax were embedded in the silicon frames of the drive units with a parylene layer, followed by magnetization by an 8 T pulse magnetic field to obtain permanent micromagnets. The motion of the center moving stage can be controlled by the drive units. To obtain an in-plane displacement in the XY axes, compensation coils were fabricated in a print circuit board (PCB) to eliminate the Lorentz force in the Z axis. The application of a direct current (DC) allowed the center moving stage to move in the XY axes by 55 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> and rotate almost 3 degrees around the Z axis, respectively. The resonance frequencies of the motion in the XY axes and the rotation around the Z axis were 630 Hz and 675 Hz, respectively.

Microwave Plasma-Enhanced Parylene-Metal Multilayer Design from Metal Salts.

In this paper, a new approach for the synthesis of Parylene–metal multilayers was examined. The metal layers were derived from a metal salt solution in methanol and a post-drying plasma reduction treatment. This process was designed as a one-pot synthesis, which needs a very low amount of resources and energy compared with those using electron beam sputtering processes. The Parylene coatings were obtained after reduction plasma treatments with Parylene C. Therefore, a Parylene coating device with an included plasma microwave generator was used to ensure the character of a one-pot synthesis. This process provided ultra-thin metal salt layers in the range of 1–2 nm for layer thickness and 10–30 nm for larger metal salt agglomerates all over the metal salt layer. The Parylene layers were obtained with thicknesses between approx. 4.5 and 4.7 µm from ellipsometric measurements and 5.7–6.3 µm measured by white light reflectometry. Tensile strength analysis showed an orthogonal pulling stress resistance of around 4500 N. A surface roughness of 4–8 nm for the metal layers, as well as 20–29 nm for the Parylene outer layer, were measured. The wettability for non-polar liquids with a contact angle of 30° was better than for polar liquids, such as water, achieving 87° on the Parylene C surfaces.

Adhesion enhancement strategy for Parylene C substrate by nanograss technique

Parylene C is a commonly used polymer in the micro-electromechanical systems (MEMS) field because of its excellent barrier property and process compatibility with other microfabrications. Whereas, the poor adhesion of other materials to Parylene C is the urgent challenge that restricts its real applications. This work proposed a strategy to enhance the adhesion between Parylene C or metals and the Parylene C substrate. A short-time oxygen plasma reaction ion etching process with ambient titanium in the etching chamber is introduced between the first layer of Parylene C film deposition (the substrate) and the second Parylene C or metal coatings. Parylene C nanostructures (nanograss) are generated on the substrate because of the oxygen plasma bombarding with sputtered titanium nanoparticles as nanomasks. Different feature sizes of nanograss were successfully obtained by tuning the RF power, oxygen flow rate and etching times. Scanning electron microscopy images showed that both the nanograss density and height (0.61 ± 0.02 μm–0.76 ± 0.03 μm) were positively proportional to the etching time with low RF power (150 W) and oxygen flowrates (60 sscm). Scratch tests are conducted after the second layer of Parylene C or metal coatings to quantitively analyze the adhesion enhancement. The results indicated that the adhesion of both Parylene C and metal on the Parylene C substrate with nanograss structures were enhanced up to around 7 and 15 times, respectively, compared to those on untreated substrates. This nanograss technique-based adhesion enhancement approach is easy-to-realize, robust, chemical-free, precisely controllable, thereby holds promising potentials in various Parylene MEMS applications.

Nanocomposite parylene-C memristors with embedded Ag nanoparticles for biomedical data processing

Neuromorphic networks adopt human brain mechanisms and create a promising way to solve various artificial cognitive problems. Memristors, novel circuit design elements, could play the role of hardware synapses in such systems. Memristors based on parylene, safe material for usage within the human body, have already shown their eligibility for neuromorphic applications. The embedding of metal nanoparticles into the parylene layer leads to even better memristive characteristics, but the usage of such memristors in neuromorphic systems is still questionable. In this paper, the characteristics of nanocomposite poly(chloro- p -xylylene) memristors are studied, and the possibility of their training following spike-timing-dependent plasticity rules is demonstrated. Furthermore, a simple spiking neuromorphic network based on such memristors is successfully simulated to solve the task of breast cancer data classification. The results pave the way towards bio-compatible and energy-efficient wearable neuromorphic systems based on parylene memristors. • Parylene-C memristors with embedded Ag nanoparticles are studied for the first time. • These devices demonstrate suitable for neuromorphic applications characteristics. • Studied memristors support bio-inspired STDP learning rules. • Simulated memristive spiking network demonstrates decent classification accuracy.

Thermal scanning probe lithography using Parylene C as thermal resist

Thermal scanning probe lithography is a direct-write patterning method that uses a heated scanning probe tip to remove thermal resist. The most widely used thermal resist is polyphthalaldehyde. Another alternative thermal resist, Parylene C is introduced in this letter. It has been found that Parylene C has a wide process latitude as a thermal resist under our experimental conditions. A high resolution of ∼40 nm can be achieved in our optimised process. In addition, patterns in parylene layer can be transferred directly into the substrate with deep reactive ion etching without an additional hard mask, thus simplifying the fabrication process.

Capacitive Stretchable Strain Sensor With Low Hysteresis Based on Wavy-Shape Interdigitated Metal Electrodes

In this work, a stretchable thin film capacitive strain sensor based on wavy-structured interdigitated metal electrodes is successfully demonstrated. Wavy-shape metal electrodes were patterned using bulk silicon micromachining, endowing the electrodes with high stretchability and reliability. The electrodes were also protected with a layer of parylene C to prevent damage during stretching and embedded in polydimethylsiloxane (PDMS) stretchable package layers. The interdigitated electrodes sitting on the wavy structures experienced a waving angle change under external strain resulting in capacitive change, which is the sensing mechanism of the wavy structured interdigitated capacitive strain sensor (WICSS). The sensitivity and stretchability of the WICSS is dependent on the design of interdigitated electrodes and the dimension of the wavy structures. The gauge factor (GF) of the WICSS was 0.27 at 25% strain. There was little hysteresis during the stretching and releasing process in the range of 25% strain. The sensing property remained stable within a 1000 cycling test. The applications of the high-performance WICSS are also demonstrated by detecting the motion of human fingers and wrists.

Breathing Parylene-Based Nanothin Artificial SEI for Highly-Stable Long Life Three-Dimensional Silicon Lithium-Ion Batteries

Here, we present on the application and characterization of parylene layers of nanometric thickness as a highly efficient artificial elastic SEI layer for three-dimensional nano-silicon anodes. The simple deposition process of the parylene layers creates an extremely conformal layer, even on the most complex three-dimensional substrate geometries and can be easily controlled down to thicknesses of below 30nm with excellent uniformity. The parylene nanothin layers are shown to be extremely stable chemically, electrochemically and mechanically, while notably allowing the free diffusion of Li-ions into the Si underlying active layer. The elasticity of the organic parylene layer plays a key role in the applicability of parylene to act as an efficient artificial SEI structure, as it was shown to be capable to withstand the dramatic natural "breathing" effect of the underlying silicon nanostructures, without interruption to the active material volumetric changes, while partially preventing and slowing the formation of a secondary SEI layer. Combined with our unique, novel substrate which demonstrates a simple catalyst-free growth of highly electrically conductive Si-stainless steel composite anodes with high loadings of silicon nanostructures and binder-free nature, remarkable electrochemical results can be achieved. Electrochemical characterization reveals that the Parylene-F VT-4 nanolayer is superior to other parylene types, exhibiting more than 450 cycles with 75% capacitiy retention vs Li metal anode. Importantly, the parylene layer does not allow delamination and cracking of active Si material, as evident from the 95.5% capacity retention after 400 cycles at low C-rate. The unique combination of the parylene artificial SEI layer and highly conductive substrates allow for high C-rates (>2C) to be achieved with significant capacity retention. The parylene layer is shown to dramatically improve the anode cycle life compared to bare silicon-based anodes, while not limiting the active material loading degree achievable. Most importantly, parylene is shown to fulfill all the required properties of artificial SEI, including impeccable chemical stability in organic solvents, elasticity and mechanical stability, high adhesion to the silicon under-layer, lowering the SEI formation, ionically conductive and electrically insulating and cost-effective, scalable and simple fabrication. The simplicity, applicability and control of parylene deposition, along with its vast improvement of stability of bare silicon anodes, make it an excellent candidate for future applications as an efficient artificial SEI layer for next-generation silicon anodes and other active materials of interest. Figure 1

Breathing parylene-based nanothin artificial SEI for highly-stable long life three-dimensional silicon lithium-ion batteries

Here, we report on the application and characterization of parylene (poly p-xylylene) layers of nanometric thickness as a highly efficient artificial elastic SEI layer for three dimensional nanosilicon anodes. The simple deposition process creates an extremely conformal layer, even on complex 3D substrate geometries. The deposition process can be easily controlled down to thickness of 30 nm with excellent uniformity. The parylene nanothin layers were shown to be extremely stable, chemically, electrochemically and mechanically, while notably allowing the free diffusion of Li-ions into the Si underlying active layer permitted by the finite solvent diffusion through the polymeric layer. The elasticity of the organic parylene layer plays a key role in the applicability of parylene to act as an efficient artificial SEI structure, as it was shown to be capable to withstand the dramatic natural “breathing” effect of the underlying silicon nanostructures, without interruption to the active material volumetric changes, causing no additional stress on the silicon structures, while partially preventing and slowing the formation of a secondary SEI layer. Electrochemical characterization reveals that parylene VT-4 (parylene F) layer is superior to other parylene types, exhibiting >500 cycles with >75% capacity retention, dramatically improving the anode cycling life compared to bare silicon-based anodes, while not limiting the active material loading degree achievable. Importantly, the parylene layer efficacy in preserving the silicon active material is determined via 95.5% capacity retention at low c-rates. The simplicity, applicability and control of parylene deposition, along with its vast improvement of stability of bare silicon anodes, make it an excellent candidate for future applications as an efficient artificial SEI layer for next-generation silicon anodes and other active materials of interest.

3D-structured soft bioelectronic devices with crack-free metal patterns

Three-dimensionally (3D) structured soft electronic devices that fit the contour of target organs or tissues are preferred for the stable implantation of biomedical devices. However, the metal patterns deposited on soft materials, especially polydimethylsiloxane (PDMS), can generate microcracks or disconnections following an expansion of the substrate. A way to generate 3D structured soft devices is using fluid injection into the unbonded area of a selectively bonded 2D structure comprised of PDMS and parylene layers. This work outlines the development of 3D soft bioelectronic devices, including the fabrication processes optimized for stable metal patterns even after substrate expansion via fluid injection. The generation of cracks in metal patterns was significantly affected by the sputtered material for plasma mask during the selective bonding process and the thickness of the intermediate parylene layer used underneath the sputtered metal. An RF-sputtered titanium mask was chosen to create crack-free metal patterns on the intermediate parylene layer based on PDMS substrate. Moreover, the thickness of the intermediate parylene layer was optimized using finite element analysis for stable and intact metal patterns after fluid injection. The developed soft bioelectronic device successfully demonstrated the ability to record and stimulate the peripheral nerve in vivo as cuff electrodes. The optimized processes developed in this study not only enable soft 3D electronic devices applicable to internal organs or tissues with 3D curvatures, but also suggest a promising way to fabricate flexible electronics using conventional micromachining processes such as photolithography and metal sputtering on soft and expandable substrates.

Assessment of transfer of morphological characteristics of Anomalous Aortic Origin of a Coronary Artery from imaging to patient specific 3D Printed models: A feasibility study

Background and ObjectiveThis study aims to determine the accuracy of patient specific 3D printed models in capturing pathological anatomical characteristics derived from CT angiography (CTA) in children with anomalous aortic origin of a coronary artery (AAOCA). Methods & MaterialsFollowing institutional regulatory approval, a standardized protocol for CTA of AAOCA was utilized for imaging. Blood volume of the aorta and coronaries were segmented from the DICOM images. A total of 10 models from 8 AAOCA patients were created, including 2 post-operative models. Mechanical properties of Agilus30 a flexible photopolymer coated with a thin layer of parylene, polyurethane (PU) and silicone and native aortic tissue from a postmortem specimen were compared. AAOCA models with wall thicknesses of 2mm aorta and 1.5mm coronaries were 3D printed in Agilus30 and coated with PU. CT of the printed models was performed, and 3D virtual models were generated. Transfer of anatomical characteristics and geometric accuracy were compared between the patient model virtual models. ResultsDynamic modulus of Agilus30 at 2mm thickness was found to be close to native aortic tissue. Structured reporting of anatomical characteristics by imaging experts showed good concordance between patient and model CTA Comparative patient and virtual model measurements showed Pearson's correlation (r) of 0.9959 for aorta (n=70) and 0.9538 for coronaries (n=60) linear, and 0.9949 for aorta (n=30) and 0.9538 for coronaries (n=30) cross-sectional, dimensions. Surface contour map mean difference was 0.08 ± 0.29mm. ConclusionsGeometrically accurate AAOCA models preserving morphological characteristics, essential for risk stratification and decision-making, can be 3D printed from a patient's CTA.

Mechanical characteristics of metal nanoparticle thin film on flexible substrate exposed to saline solution

The robust and reliable mechanical characteristics of metal nanoparticle (NP) thin films on flexible substrates are important because they operate under tensile, bending, and twisting loads. Furthermore, in wearable printed electronics applications, salty solutions such as sweat and seawater can affect the mechanical reliabilities of devices. In this paper, we investigated the effect of sodium chloride (NaCl) solutions on silver (Ag) NP thin films on flexible polymer substrate. After exposure to NaCl solution of Ag NP thin film, we observed the aggregation behavior between Ag NPs and formation of larger pores in the film due to the removal of organic capping layer from the surface of Ag NPs. The average porosity and 5% deviation strains of Ag NP thin films on the polyimide substrate were dramatically increased and decreased from 2.99% to 9.64% and from 3.94% to 0.87%, respectively, after exposure to NaCl solution for 1 h. Also, we verified a drastic deterioration of the surface adhesion of the Ag NP thin film to the substrate by exposure to NaCl solution. We could observe crack propagation and delamination by in-situ scanning electron microscope imaging. In addition, passivation effect by a parylene layer for preventing the permeation of the saline solution was investigated.