The spherical shape also enables all scattering sites to be equally effective, increasing the utility of HL particles. In addition to the use of HL particles as pigments, these particles can be further functionalized by immobilizing amine containing compounds on the particle surface. An example is immobilization of 5 wt.% chitosan or 14 wt.% polyethyleneimine (PEI).
The amine-functionalized HL particles effectively adsorbed formaldehyde, a carcinogenic gas that is often released from plastics, furniture and textile finishing [14].
The formaldehyde adsorbent activity of HL–chitosan particles was found to be greater than that of HL–PEI. FTIR spectra revealed that chemical adsorption occurred via the electrophilic addition of amine to carbonyl of formaldehyde followed by elimination of water.