[078] To demonstrate the application of the textile based TENG as a C02 sensor, polyethylenimine (PEI) solution was spray coated onto the PEDOT:PSS functionalized textile surface. The cotton fabric is coated with non-diluted PEDOT:PSS solution in this section to achieve a better conductivity. The PEI gel was diluted 10-fold with Dl water for spray coating. To perform the contact-release cycle, the frequency of the moving stage is set as 0.5Hz and the force is set as 10N. With the absorption of C02 after spray or injection between the sensory textile 1102 and substrate 1104 as shown in the schematic diagram of the test setup of PEI coated CO2 sensing textile in FIG. 11(a), a carbamate layer 1106 which is a C02-PEI complexation will be formed and in turn change the electronegativity of the PEI layer 1102. This electronegativity change can be projected on the transferred charges of the triboelectric nanogenerator. The transferred charge or charge responses on the sensor over varying CO2 concentration of the textile based TENG with triboelectric negative material of PTFE and PET (contact layer) is depicted in FIG. lib. 

[079] The transferred charge Q increases with CO2 concentration and the Q almost saturates when the CO2 concentration reaches lOOOOppm for both devices. For the TENG with PTFE as negative triboelectric material, the transferred charge increases from 5.35nC to 7.67 nC where it reaches its saturation, with a sensitivity of 2.69 χ 10-4 nC/ppm. 

[080] PEDOT:PSS coated smart socks 

[081] Smart socks as triboelectric energy harvester with piezoelectric force sensor 

[082] Mechanical energy from the motion of foot is considered a significant power source that can be converted into electricity through the triboelectric effect. Previous studies have mainly focused on insole energy harvesters. PEDOT:PSS coated smart socks are able t o make the textile itself into an effective triboelectric material due to the conductivity of the coating. Hence, as shown in FIG. 12(a), socks have been designed in accordance with present teachings to generate power while being more compact and comfortable for wearing than a generator incorporated directly into the sole of the shoe. FIG. 12(a) shows PEDOT:PSS coated socks 1200 and the original socks 1202. FIG 12(b) shows the as-fabricated PZT sensor arrays 1204 on PDMS substrate 1206 (before being embedded into socks), and FIG. 12(c) is a close-up of a single PZT sensor unit 1208 with top and bottom electrode. 

[083] FIG. 13 shows the measured output power under difference scenarios. Within shoes, each sock can provide the maximum power of 137W and 66W for jumping/running and walking, respectively. Without shoes, as the space of complete triboelectric contact/release cycle increases, the output power can be further boosted up to 1.7mW and l.lmW. PTFE film is used as negative contact material during the test. As shown in FIGs. 12b and 12c, to achieve 

