Synthesis of quaternary poly(4-vinyl pyridine) based submicron particles for preparing biocidal dispersions and permanent antibacterial cotton fabrics

Manufacturing of antibacterial materials have found great interest in recent years. Especially their synthesis from cheap sources has been popular area of research. However, their use as disposable material makes the process uneconomical. Therefore, to create reusuable materials is beneficial not only for the economical reasons but also for avoiding repetation of the application process. In the present work, we have targeted to permanent antibacterial cotton fabrics. However, chemical attachment of the biocidal functions onto a natural polymer such as cellulose is very tedious work which is deterred to employ in practice. It was concluded that permanent antibacterial material can be formed either on woven or nonwoven fabrics by crosslinking polymerization in fibrillar matrix of the fabric without covalent attachment. For this purpose, polymerization of 4-vinylpyridine in the presence of alkyl halides resulting in spontaneous polymerization was chosen. To generate crosslinking structure we have used dihalides as crosslinking agents. Generation of such a structure a simple in which 4-vinylpyridine, mono alkyl halide and 1,6-dibromohexane were left to contact with the certain amount of a dry fabric for overnight. The reaction takes place at room temperature. At the end of the reaction the fabric is washed several times with water in the presence of commercial detergents. Dried fabric obtained was still soft and colorless. Presence of the quaternary polymer (polyquat) was simply confirmed by colorination of the fabric when contacted with anionic dyes such as, phenyl red, bromothymol blue, methyl orange and Denactive Blue Derf. Strong colorination of the fabric samples revealed presence of the polyquat in the structure of the cotton fabric. In order to investigate the reaction conditions of the polyquat formation the crosslinking polymerization was performed in acetonitrile. This process gave submicron size forming stable dispersions in alcohol and water. DLS measurements and SEM images showed that sizes of the particles are in 150 nm – 1000 nm. It was demonstrated that the dispersions of the crosslinked particles have antibacterial activity against Gram-negative bacteria E. coli in 5% concentrations. The particle also undergo rapid colorization in the presence of the dyes discussed above. What we learnt from this study is that both free and attached polyquats possess dyeabilities. The most striking outcome of this work is possibility of generating polyquats in the fibrilles of the cotton fabric without covalent attachment. This approach is expected to find different applications in fabrication of numerous textile materials. Considering failures of the current production processes the method presented here is very promising especially in manufacturing of special wears such as, bedsheets, aprons and various households. The materials obtained would be superior to the current products as permanent antibacterial. The bacteria killing method presented can be extended to manufacturing of paper based antibacterial goods as well. It can be replaced with the volatile disinfectants which are currently used.