(PEEK) (medium melt viscosity grade 450 PF) was obtained from Victrex
PLC, England, and 3-aminopropyl trimethoxysilane (99%) was received
from Sigma-Aldrich Chemicals. Graphite (Gt) powder (size 100 μm),
dimethylacetamide (DMAc), phosphoric acid, formaldehyde, acetone,
methanol, H2SO4, NaOH, NaCl, NaNO3, KMnO4, H2O2, HCl, and Na2SO4 of analytical grade were obtained from SD Fine Chemicals,
India and used with proper purification. All experiments were performed
using ultrapure water (resistivity: 18.2 MΩ cm).