Surface resistance measurement conductive fabrics

To better understand the diffusion-limited school of thought mentioned above, it is worth digressing momentarily on another noble -metal electrode system silver on YSZ. Kleitz and co-workers conducted a series of studies of silver point-contact microelectrodes, made by solidifying small (200—2000 //m) silver droplets onto polished YSZ surfaces. Following in-situ fabrication, the impedance of these silver microelectrodes was measured as a function of T (600-800 °C), P02 (0.01-1.0 atm), and droplet radius. As an example. Figure 9a shows a Nyquist plot of the impedance under one set of conditions, which the authors resolve into two primary components, the largest (most resistive) occurring at very low frequency (0.01—0.1 Hz) and the second smaller component at moderately low frequency ( 10 Hz). 

Antistatic fibres may be in the form of stainless steel fibres (see Bekaert), or polyester fibres coated with a layer of conducting material such as carbon (see Epitropic fibres) or silver (see SilveR.STAT ). Depending on the efficiency of the blending system, the addition of 2-5% of these fibres is normally recommended to ensure satisfactory dissipation of any static charge. The effectiveness of such additions may be assessed by measurement of the fabric s surface resistivity (see BS 6524 1995 part 4), a value of 10 ° Q. square" being considered adequate for most applications (NB, the size of the square is irrelevant). 

Fig. 35. Surface resistance of various textile products. The electrical properties of fabrics are measured by the surface or sheet resistance and expressed in ohms/square (/2/D). Although volume resistance or volume conductance of the composite structure may be determined, these values are relatively meaningless as textiles, like foams, may contain large amounts of air.

Another study by Hong et al. also reports the preparation of conducting PANI/nylon-6 composites with high electrical conductivity and superior mechanical properties, such as flexibility and lightness [24]. PANI was chemically polymerized on the surface of the nylon-6 electrospun nanofiber webs. The electrical conductivity measurements showed that the conductivity of the PANI/nylon-6 composite electrospun fiber webs was superior to that of PANI/nylon-6 plain-weave fabrics because of the high surface area/volume ratios. The volume conductivities of the PANI/nylon-6 composite electrospun fiber webs increased from 0.5 to 1.5 S cm as the di sion time increased from 10 min to 4h because of the even distribution of PANI in the electrospun fiber webs. However, the surface conductivities of the PANI/nylon-6 composite electrospun fiber webs somewhat decreased from 0.22 to 0.14 S cm as the di sion time increased, probably because PANI was contaminated with aniline monomers, aniline oligomers, and some alkyl chains, which served as electrical resistants. 

The plausible explanation for the relatively high resistance can be found in die structure of jersey. There is not a natural padi for the current to flow as it hiqipetis udien the resistance is measured in the course direction. The current flows throughout each contact between a loop located of die previous course and a loop of the course immediately located above (or below). This results in a small metallic contact surface, thus resulting in a higher resistance. On the contrary, the electrical conductivity of jersey fabric when measured in a course direction is quite inoeased since the yam is part of each loop of that course. As a consequence, the renstance dramatically decreases. 

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