*2.2. Synthesis of PCL/TiO2 Nanocomposites*

PCL/TiO2 polymer-ceramic hybrid composites containing 2, 5 and 7 wt % of the ceramic content was synthesized by means of the electrospinning process. In brief, poly(ε-caprolactone) (PCL, 80 kDa; Sigma-Aldrich, Singapore) pellets were dissolved in chloroform and methanol (Sigma-Aldrich, Singapore) at 3:1 ratio to make an 8% (*w*/*v*) solution and kept under stirring conditions for 4 h. TiO2 was synthesized as reported earlier *via* electrospraying method by using titanium isopropoxide as the main precursor [34]. To prepare PCL/TiO2 nanocomposites with a certain PCL to TiO2 ratio, a known amount of TiO2 (2, 5 and 7 wt %) powders were added into the solution batch wise under string conditions. Because of the nature of TiO2 nanoparticles, it was very critical to homogeneously disperse TiO2 nanoparticles in the PCL matrix to acquire satisfactory dispersion without agglomeration. The mixed solution was under stirring conditions for 72 h using a magnetic stirrer with sonication for every 6 h. Upon attaining satisfactory homogeneous conditions, PCL/TiO2 solution was taken in a 5 mL syringe equipped with a 22-gauge rounded metal needle. A constant flow rate was set to optimized 500 μL/h through a syringe pump (NE1000, U.S.A). A constant high voltage of 12.0 kV was applied to the needle tip which was positioned at a distance of 10 cm from the grounded collector. Previously cut cpTi substrates of dimensions 10 mm × 10 mm × 2 mm were fixed on the aluminum foil as a collector. Prior to the coating procedure, the substrates were washed, sonicated in dry ethanol for 1 h and left overnight for drying. After the coating procedure, all the samples were dried under vacuum for 1 day to completely remove any solvent residues present.
