Analyzing self-assembled nanolayer films on cotton

Analyzing self-assembled nanolayer films on cotton 

Recent work by our research group, Hyde et has demonstrated that the LbL deposition of oppositely charged polyelectrolytes can be used as a method of surface modification for cotton fibers and fabrics. The cotton fibers were functionalized by reacting 2,3-epoxypropyltrimethylammonium chloride with the hydroxyl groups of cellulose to create cationic charges. These cationic charges were used to deposit subsequent layers of PSS and PAH. 

XPS and transmission electron microscopy (TEM) were used to characterize the multilayer structures over the cotton fibers. XPS spectra provided an analysis of the chemical groups present on the outermost layer of the samples. Specifically the presence of nitrogen and sulfur was monitored as it related to the deposition of PSS and PAH respectively. The ratio of N/S on the outermost layer was found to be in quantitative agreement with previously published work that deposited PSS and PAH on synthetic substrates. 

2 XPS survey spectra of cationized cotton and cotton supporting 20 alternating layers of PSS and PAH. 

The figure also shows a survey spectrum of a 20-layer PSS/PAH multilayer film deposited on a woven cationic cotton substrate. It can be seen that the peaks at 398.91 and 164.91 eV have increased in magnitude in comparison with those present in the cationic cotton sample, indicating the presence of a multilayer film. The peaks correspond to nitrogen and sulfur respectively. 

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