Q.Which of the following information is given by FTIR technique?
a. Absorption of functional groups
b. Particle size
c. Confirmation of formation of nanoparticles
d. Crystal structure

Nanomaterials are synthesised by two broad approaches: bottom-up, where molecular components self-assemble atom by atom, molecule by molecule and cluster by cluster into larger structures (e.g. nanoparticle synthesis by colloidal dispersion), and top-down, where bulk material is progressively broken down into finer and finer pieces until only a few atoms remain (mechanical disassembly of bulk solids). A key wet-chemical route is the sol-gel process, used mainly for oxide materials: a sol (a dispersion of 1-100 nm colloidal particles in a liquid) is converted into a gel (an interconnected rigid network) via hydrolysis of a metal alkoxide (MOR + H2O -> MOH + ROH) followed by polycondensation (MOH + ROM -> M-O-M + ROH), then carried through ageing, drying and thermal dehydration (heating up to 800°C) -- a process also used industrially to make water-repellent coatings for vehicle windscreens and mirrors. Once synthesised, a nanomaterial is characterised using dedicated analytical instruments: UV-visible spectroscopy gives a preliminary confirmation that nanoparticles have formed; X-ray diffraction (XRD) gi …