Abstract
This work deals with the use of hydrotalcite nanoparticle post-diffusion in layer by layer (LbL) coatings with the aim of improving their flame retardant action on cotton. The selected LbL components, which encompass polydiallyldimethylammonium chloride and deoxyribonucleic acid, aim at the deposition of an intumescent coating. Infrared spectra pointed out a super-linear growth of the investigated assembly, indicating the ability to deposit thick coatings while maintaining a relatively low deposition number. A post-diffusion process, performed by exposing the LbL-treated fabrics to two different concentrations of hydrotalcite water suspensions (0.1 or 1 wt %), was carried out to improve the fireproofing efficiency of these coatings. Coatings treated with the lowest concentration suspension partially swelled as a consequence of their structural rearrangements while the use of the highest concentration led to nanoparticle aggregates. Horizontal flame spread tests were used for assessing the achieved flame retardant properties. The post-diffusion performed at the lowest hydrotalcite concentration lowers the minimum number of Bi-Layers required for obtaining cotton self-extinguishment while samples treated with the highest concentration showed detrimental effects on the performances of treated fabrics. This behavior is ascribed to the effects of hydrotalcite particles on the intumescence of LbL coatings, as evidenced by the morphological analyses of post-combustion residues.
Highlights
In recent years, layer by layer (LbL) assembly has attracted the interest of the scientific community as a powerful tool for the surface modification of materials capable of constructing finely controlled nanocoatings
The assembly growth of the polydiallyldimethylammonium chloride (PDAC)/DNA pair has been assessed by infrared spectroscopy
infrared spectroscopy (IR) spectroscopy pointed out the super-linear growth of selected polyelectrolytes that are capable of assembling thick coatings, even at relatively low BL number
Summary
Layer by layer (LbL) assembly has attracted the interest of the scientific community as a powerful tool for the surface modification of materials capable of constructing finely controlled nanocoatings. The fundamentals of this deposition technique can be dated back to the 1960s when. The technique is based on the alternate adsorption on a substrate of polyelectrolytes, nanoparticles, etc., on the basis of a specific interaction occurring in between the selected chemical species [2]. The most widely employed interaction is the electrostatic attraction occurring between nanoparticles or polyelectrolytes in aqueous media; in addition, other interactions have been exploited such as donor/acceptor [3], hydrogen bonds [4] and covalent bonds [5].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
