Fig. 2. (a–d) Titration curves for specimens S1–S4 and (e–h) extent of the agglomeration (flocculation) value of the GNs with a change in the pH of the solution, respectively. (i–l) Color of specimens S1 to S4 in different pH environment starting from 2 to 12, respectively. (m) Experimental design to capture a digital photograph of the specimen in different pH environment and simultaneous determination of the pH value by Android application.
