Effect of Tensile Load on Electrical Resistivity of Stretchable Conductive Ink (SCI)

To date, research has tended to focus on emerging Electrical Conductive Adhesive (ECA) with stretchable and flexible substrate or known as Stretchable Conductive Ink (SCI). SCI is more flexible, stretchable and multi-purpose compare with the traditional printed circuit. Limitation on the chatacreization of SCI performance especially on it electrical performane under tensile stress has motivate this study. The aim of this research is to investigate the conductivity of the conductive ink under tensile stress at different elongation. The conductive ink carbon black was used to print on the thermoplastic polyurethane (TPU) and cure in the oven at 120°C for 30 minutes. The conductive ink was clamp using in-house stretching equipment with different elongation. The resistivity was measured by four-point probe while surface structure was observed by using Axioscope 2 MAT microscope. The result shows that the resistance increased when the elongation increased. For 40mm length of conductive ink, the initial resistance is 0.562 kΩ and its become 1.217 kΩ when stretch until 18% of its initial length. The sheet resistance of the conductive ink also increased due to the defection (porosity) on the surface of conductive ink after stretching. The strain level for 40mm and 60mm also increase form 0.14 to 0.16 that cause incerase in resistance. However, since there are no crack/defection observes at 80mm after maximum elongaton, the resistance start to decrease that cause increase in SCI conductivity

The effect of different shape pattern of metal interconnects on the electrical and mechanical properties of stretchable conductive circuit

Electrically conductive adhesive (ECA) had been extensively studied to replace the Sn/Pb solder mainly found in printed circuit boards (PCBs) because of their harmful action towards human health and environment. In the production of stretchable PCBs, ECA mainly comprises of metallic filler and polymer matrix should perform good electrical and mechanical properties when straining being loaded. Therefore, determining the optimum shape pattern to be printed will contribute toward the desired traits of stretchable PCBs. In this study, commercial silver ink and thermoplastic polyurethane (TPU) as substrate was used. The ink was printed on the substrate by doctor-blade technique with different shape patterns with varies widths (1mm, 2mm and 3mm): (a) straight, (b) zigzag, (c) square and (d) sinusoidal. Then measurement of sheet resistance by four-point measurement was conducted on unloaded and loaded straining of shape pattern. This study exhibited that 3mm width zig zag shape pattern can elongate the highest straining (5% strained) compare than others patterns. In the meanwhile, straight and square shape pattern did not tolerate to any deformation which when straining at a minimum elongation of 0.1mm, the conductivity already lost. In conclusion, further study purpose, more analysis were suggested like analysis on the silver composition, curing temperature variation as well as the distribution of stress in printed shape pattern by 3D Finite Element Analysis (FEA) can be done for the more reliable study

Mechanical and Electrical Characterization of Nanocomposites Liquid-Solid Conductive Ink on Polyethylene Terephthalate (PET) Substrate

With drastic development of wearable electronics have urged the studies on the conductive ink and flexible substrate. Wearable electronics consist of nanocomposites liquid-solid conductive ink and flexible substrate such as polyethylene terephthalate (PET). They were produced by using stencil printing method. This paper presents the mechanical and electrical characteristics of  conductive ink with unloaded condition. The conductive ink was printed with four patterns, which were straight, curve, square and zig-zag patterns. Then, all four patterns were tested for their surface morphology, surface roughness, sheet resistivity and bulk resistivity. Surface morphology showed that conductive ink with 3 mm width had less granular particle formed than conductive ink with 1 mm width. Surface roughness of conductive ink with 3 mm width was smoother compared to 2 mm width and 1 mm width. Sheet resistivity and bulk resistivity results indicated that resistivity of all four patterns decreased with the increase of the conductive ink width. From the result, it showed that conductive ink with straight pattern has the best performance. Meanwhile, individual result for each pattern had its own function inside the circuit track.

Correlation analysis of biodegradable additives, temperature and loading toward tribology behaviour of musa aluminata balbisiana (MBS) oil

Identification of the effect of the tribological characteristics in lubricant application is a critical part of the experimental process. A correlation study is used to identify the effect of temperature, load and biodegradable additive on the coefficient of friction (COF) and specific wear (Ws) from the experimental data. Pearson correlation coefficient (r) and analysis of variance (ANOVA) are the statistical analysis used to identify the relationship between the parameters and the significant difference in response variable which are COF and Ws. Based on the result, there is a positive moderate linear relationship between temperature to both COF and Ws with a score of r between 0.354 to 0.676. In contrast, there is a negative linear relationship between load towards COF and Ws with a -0.285 to -0.460 score of r. There is approximately no correlation with the percentage of biodegradable additives respecting COF and Ws. The result also shows that there is no significant difference between COF and Ws using ANOVA testing with a p-value is more than 0.05. This work may facilitate improvements for other researchers to identify the variable in the experimental design proces

Nanoscale Graphene Nanoparticles Conductive Ink Mechanical Performance Based On Nanoindentation Analysis

Common conductive inks can be classified into three categories, which are noble metals, conductive polymers and carbon nanomaterials. Carbon nanomaterials offer many potential opportunities to be applied in printed and flexible electronics. Therefore, this paper aims to produce highly functional conductive ink using graphene nanoparticles with epoxy as a binder. As a baseline, graphene-filler conductive ink was formulated using a minimum percentage at the beginning. Then, the filler loading was increased based on the required conductivity level. This is to make sure the materials are in contact with each other and the movement of an electron will become easier. The formulation of ink, mixing process, printing process and curing process were performed to produce highly conductive graphene ink. The electrical and mechanical properties were assessed using a Four-point probe as per ASTM F390 and Dynamic Ultra Micro Hardness (DUMH) test as per ASTM E2546-1. Graphene Nanoplatelet (GNP) aggregates are unique nanoparticles consisting of shorts stacks of graphene sheets with platelets shape. They typically consist of aggregates of sub-micron platelets that have a particle diameter less than 2 microns, typical particle thickness of a few nanometers, a bulk density of 0.2 to 0.4 g/cc, an oxygen content of 98 wt%, and in the form of black granules. In this paper, the effect on sheet resistivity and nanoindentation for straight line-shape, curve-shape, square-shape and zigzag-shape circuits printed on Thermoplastic Polyurethane (TPU) substrate using Graphene Nanoparticles (GNPs) conductive ink as the connection material were investigated. The samples in this study were fabricated using a screen-printing method with a fixed circuit width of 1 mm, 2 mm and 3 mm. The straight-shape circuit, curve-shape, square-shape and zig-zag-shape circuits represent the electrical connection with 180°, A°, 90° and B° directional angles. The effect of varying circuit width on the sheet resistivity of all printed circuit mentioned before was later measured using Four-point probe. Nanoindentation was conducted using instrumental machines with indenter load and indenter displacement that can be continuously and simultaneously recorded during indenter loading and unloadin

Comparative Evaluation Of Biodegradable Additives Of Ethyl Cellulose (EC) And Ethylene Vinyl Acetate (EVA) On Tribological Properties Of MBS Oil

The effect of biodegradable additives of Ethyl cellulose (EC) and Ethylene Vinyl Acetate (EVA) on tribological properties of oil extracted from banana peel waste of Musa Aluminata Balbisiana (MBS) was evaluated. The presence of EC and EVA at difference strength of concentration leads to reduction in COF, WSD and Ws values for MBS oil. The addition of 4.0% w/w of EC and EVA in pure MBS oil at the parameter of 27 ºC and 100 N of applied load were lead to reduction in WSD and Ws. However, unlike with the COF results, addition of EC and EVA on MBS oil did not show very significant reduction either in WSD or in Ws.Therefore, they would not effectively act as anti-wear properties. It can be inferred that, at the low temperatures and strength, EC is more effectives to lead to the reduction of COF in MBS oil than EVA. Lower COF values of MBS oil with presence of additive of EC and EVA suggest that the indicative of the formation of protective tribo-chemical film, which was promoted by the tribochemical reaction due to the rubbing action and chemical interaction of EC and EVA with MBS oil. MBS oil with addition of EC showed a very stable COF value compared to the addition of EVA is reflected to the strength of the boundary film formed by the oil on the surface. Surface morphology analysis on the spherical pin used in pin on disc in tribological procedures were shown to have a predominant wear mechanisms of adhesive and abrasive wear

The Influence Of Geometrical Dimensions On Electromechanical Performance In Stretchable Circuit

Stretchable conductive ink (SCI) had been extensively studied for fabricating stretchable electronic devices. In this study, silver conductive ink and thermoplastic polyurethane (TPU) were used as substrate. The ink was printed on the substrate using screen printing with different shaped patterns varied by the widths of 1 mm, 2 mm and 3 mm: (a) straight, (b) zig-zag, (c) square and (d) sinusoidal. The measurement of resistance was performed using four-point measurement during unloaded and loaded conditions of the shape pattern. This study revealed that width had influenced the resistivity in all shape patterns, where the narrow the width, the higher the resistance is. Comparative studies of electromechanical analysis of the shaped patterns had showed that a 3 mm width of zig-zag pattern had a better electromechanical performance by having stretchability to maximum of 7.78%. Straight and square shape patterns, however, exhibited the poor tolerate deformation as both failed to conduct electricity upon straining at the minimum elongation of 1.11%

The Effect Of Temperature On The Electrical Conductivity And Microstructure Behaviour Of Silver Particles

Silver conductive ink has been used in the electronics industry due to their potential advantages such as high electrical conductivity and thermal conductivity. However, silver needs to undergo a curing process to reduce the porosity between particles as well as to have a smooth conductive track to ensure maximum conductivity. Therefore, the effect of temperature on the electrical conductivity and microstructure were explored. The printing of silver conductive paste was executed on a polymer substrate through screen printing before analysis. Next, an electrical analysis was done to measure the conductivity by using a 4-point probes instrument, followed with microstructure and mechanical analysis which were carried out to observe the structure behaviour and hardness of silver respectively with respect to temperature. The study found that the electrical conductivity of silver increases when temperature elevated. Besides that, the microstructure of silver has a larger size with the increase in temperature, correspondingly cause the silver to have less hardness. In conclusion, temperature plays significant roles in increasing the electrical conductivity of silver

Comparison measurements of low resistance and high strength on synthesis graphene conductive ink filled epoxy

Stretchable and conductive materials are expected to be widely used for various electronic equipment in the future especially in the field of automotive safety. Flexibility and expandability are the main features of the Stretchable Conductive Ink (SCI) while maintaining the high conductivity levels and can be applied to electronic circuits in vehicles especially for driver health monitoring systems. The experimental work obtained the suitable formulation of the conductive ink based on the resistivity and elasticity values. Five different percentages of samples, 10 wt.% until 30 wt.% with each sample interval represents 5 wt.%. Samples of 20 wt.%, 25 wt.%, and 30 wt.% did not show significant differences in terms of the average volume of resistivity. Filler loading of 25 wt. %of GNP in the filler loading matrix produced the best results for nanomechanical properties. Low resistance and high elasticity of SCI in the vehicle electronic equipment can monitor more effectively the driver's health as SCI can be stretched according to the shape of the human body. It also has good conductivity to measure the movement of the human pulse and muscles