HARVESTING ELECTRICITY FROM HUMAN HAIR 27 metals. All voltage and current measurements were made using this “hair/silk mea- surement device”. Three different electrode confi gurations used in the study are shown in Table 1. Three different electrode confi gurations (I–III) were used for recording the current and voltages across hair and silk cocoon membrane. In confi guration I, same electrodes were used across the membrane. In confi guration II and III, different electrodes were used. For confi guration I, high-purity copper wires of 32 AWG (1.2-m long) and 32-gauge copper sheets (1 × 2 cm2 area) were used. While for confi guration II, high-purity platinum wire of 49 AWG (3-m long) and 32 gauge aluminum sheets (1 × 2 cm2 area) were used and for confi guration III, high-purity copper wires of 32 AWG (1.2-m long) and 32-gauge alu- minum sheets (1 × 2 cm2 area) were used as electrodes. We either use same copper electrode as E1 and E2 (Figure 4A), or dissimilar electrodes (Figure 4B, C). The fi gure 4A –C is showing some simple devices fabricated by us, using human hair and silk. Three different electrode confi gurations (E1:E2) were used to per- form the recordings. ELECTRICAL MEASUREMENTS The current and voltage across the measurement device was recorded using an electrom- eter Keithley’s 51∕2-digit Model 6517B electrometer/high resistance meter (Keithley Figure 7. Electrical properties of human hair and silk cocoon sandwiched between same copper electrodes (Device 1). Representative traces of current and voltage obtained from bioelectric device described in Figure 4. (A) Average (n = 6) current profi les of human hair under the two different conditions (moist and exposed to water vapor), in moist state the average current value is around 9.57185E-09 while it increases drastically to 8.65487E-06 when exposed to water vapor. (B, C) Trend is almost identical in the silk cocoon but the average current density is higher as compared to the human hair. When exposed to water vapor average current den- sity in (B) A. mylitta is 7.98428E-05 which is higher than (C) B. mori 6.48795E-05, as it has more ion species inherently present in them. (D) Average voltage recording obtained from human hair shows that there is negligible voltage when moist, while when exposed to water vapor the voltage rises sharply. (E, F) Pattern of average voltage reading of silk cocoon membrane is similar to that observed in human hair. Voltage is low in moist conditions and increases sharply, when exposed to water vapor.

JOURNAL OF COSMETIC SCIENCE 28 Instruments, Inc., Cleveland, OH). Average trace of current and voltage obtained from 10 such devices of each type of electrode confi guration is depicted in the results. The 6517A/B Electrometer/high resistance meter basic application software written on LabVIEW 8.6 was used for the recording of devices which was interfaced with computer. To fi nd the basic average of six replicates, all we had to do is add all the recording and divide the resultant by six and plot the graph in Microsoft Excel 2014. The polarities of the various devices were as follows: Device 1: copper winding as positive terminal and copper sheet as negative terminal. Device 2: platinum winding as positive terminal and aluminum sheet as negative terminal. Device 3: copper winding as positive terminal and aluminum sheet as negative terminal. HAIR BIOELECTRICAL DEVICE FOR ENERGY HARVESTING Two different confi gurations of simple bioelectrical devices were assembled. Here, we are providing the graphics of one such confi guration, where a plastic casing covered the device to ensure uniform application of water vapor on human hair. Pure deionized water was boiled to generate water vapor, which was then directed to the plastic casing using bent glass tubes subjecting the device assembly to external stimulus. When water vapor reached the bioelectric device, its temperature was around 80°–85°C (Figure 5). In the Results section, we have provided another confi guration of the same device as described below. It is just fabricated with copper and aluminum and mounted on a glass rod. Figure 8. Electrical properties of human hair and silk cocoon sandwiched between aluminum and Copper. Three different conditions were kept dry, moist, and exposed to water vapor. (A) Average (n = 6) current reading for human hair which shows the trend is almost identical to that observed in Figure 7. Behaving as an insulator in dry state and when came in contact with moisture the current values shoot up sharply. (B, C) Average current reading obtained from silk cocoon showing similar pattern as observed in previously published work (26). (D) Average voltage reading obtained from human hair. Here we cannot observe the hump around 1600 s that we observed with aluminum and platinum (Figure 9). Instead the voltage is de- creasing sharply once the water vapor was stopped. (E, F) Similar reading could be seen in silk cocoons.