## 3 Results
### Influence of AFM Chip Materials on Charge Generation  
#### 3.1.1 Influence of Mica AFM Chip on Charge Generation in Water Flow  
Firstly, generation of charge in the system for AFM-based fishing and its accumulation in the cell upon pumping of water through the injector with a peristaltic pump in the absence of an AFM chip was monitored. After that, a mica chip was placed at either \(l\) = 4 mm, \(l\) = 1 cm or \(l\) = 2 cm distance from the injector nozzle, and charge measurements were performed. The obtained \(\Delta q(t)\) dependencies are presented in Figures 2 and 3. Figure 2 displays typical time dependencies (\(\Delta q(t)\) dependencies) of charge accumulation in the measuring cell obtained in the absence and in the presence of mica chip placed at \(l\) = 4 mm distance from the injector nozzle. The inset in this figure displays typical \(\Delta q(t)\) dependencies obtained in a series of experiments upon pumping of water through the injector. One can note slight variations between \(\Delta q(t)\) obtained in the absence of mica chip (see inset). The charge accumulation rate without mica was 42 to 44 nC in 7 min, the average value was (43 \(\pm\) 1) nC in 7 min. In the presence of mica chip, an increase in charge accumulation rate was observed in comparison with the case without mica. An increased level of charge accumulation (53 to 57 nC) was observed, with an average value of (55 \(\pm\) 2) nC in 7 min. Also, one can note an insignificant variation between \(\Delta q(t)\) obtained in the presence of mica chip (see inset). Thus, in the main graph in Figure 2, averaged \(\Delta q(t)\) dependencies are presented. As seen from Figure 2, an increased rate of charge accumulation is observed when a mica AFM chip is placed near the injector nozzle--as compared to the case without the chip. The accumulation of the generated charge in the measuring cell was linearly dependent on time. When the distance between the injector nozzle and chip was 10 mm, analogously to the case with \(l\) = 4 mm, an increased level (in comparison with the case without mica chip) of charge accumulation (48 to 50 nC) was observed. In a series of three repeated experiments, an average value of (49 \(\pm\) 1) nC in 7 min was obtained (Figure 3). Figure 3 displays averaged \(\Delta q(t)\) dependencies obtained in this series of experiments. Also, analogous experiments with the distance \(l=2\) cm were carried out. No significant influence of the mica chip on the charge generation was observed at this distance. Figure 3: The influence of the presence of mica on the charge generation in water. Averaged \(\Delta q\)(\(t\)) dependencies obtained upon pumping of water through the injector. Experimental conditions: (**1**) without mica; (**2**) with mica. The distance between the injector nozzle and the mica chip is \(l=10\) mm. T = 35 \({}^{\circ}\)C. The data of one and the same experimental series obtained using one and the same tube-pipe-tip set (see the Materials and Methods section) are presented. Figure 2: The effect of the presence of mica on the charge generation in water. Main graph presents averaged \(\Delta q\)(\(t\)) dependencies obtained in a series of experiments: (**1**) without mica; (**2**) with mica. The inset displays typical \(\Delta q\)(\(t\)) dependencies obtained in a series of experiments upon pumping of water through the injector. Experimental conditions: (**1**) without mica; (**2**) with mica. The distance between the injector nozzle and the mica chip is \(l=4\) mm. T = 35 \({}^{\circ}\)C. The data of one and the same experimental series obtained using one and the same tube-pipe-tip set (see the Materials and Methods section) are presented. Figure 4 displays the dependence of the relative change in the value of charge (\(\Delta q\)/\(q\)) on the distance \(l\) between the injector nozzle and the investigated material. As one can see from this figure, a decrease in the relative value of charge accumulated in the cell in the presence of the investigated material with increasing \(l\) was observed.