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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Synthesis and characterisation of polyelectrolytes based on polymers of diallyldimethyl ammonium chloride and poly(styrene-co-butadiene)

Svensson, David January 2012 (has links)
In printed electronics there are many polyelectrolytes to choose from. While polyelectrolytes such as polystyrene sulfonic acid can fulfill many ofthe desired functionalities of a semiconductor, there is a need for other polyelectrolytes with other functionalities, such as functionality at low airhumidity and better cross-linking possibilities, while still functioning as a good semiconductor.Within this thesis, there is a description of general polyelectrolytes, as well as various usages.The synthesis and characterization of new polyelectrolytes that have been developed, based upon diallyldimethyl ammonium chloride (DADMAC)and a derivative of polystyrene sulfonic acid (PSSH) is described.The study and experimental testing of the polymers as polyelectrolytes under different conditions is described.
2

Novel biocidal formulation

Wills, Peter January 2013 (has links)
In this modern age, society has become much more aware of the danger bacteria can have on people's health. Personal and household antimicrobial formulations are commonly used within the home to lower the levels of harmful bacteria such as E. Coli, Salmonella and Pseudomonas. The active which kills the bacteria within the formulation is described as a biocide. This research looks at the often neglected potential of cationic polyelectrolyte as a biocide, firstly within solution and secondly in creating an antimicrobial surface. The solution properties and antimicrobial activity for a range of commercially available cationic polyelectrolytes (polymeric quaternary ammonium compounds (QAC) and biguanides) of differing molecular weights were investigated. All polyelectrolytes were observed to have some level of antimicrobial activity. The second phase of this research investigated polyelectrolyte/surfactant/water mixture of similar charge (cationic). Two QAC surfactants were investigated: Alkyl (C12 70%; C14 30%) dimethyl benzyl ammonium chloride (BAC) and Didecyldimethylammonium chloride (DDQ). At a critical concentration, these mixtures segregatively phase separate into a surfactant rich upper phase and polyelectrolyte rich lower phase. This phase separation phenomenon was investigated in respect of surfactant and polyelectrolyte type as well as polyelectrolyte molecular weight. Surfactant type was observed to be the dominant factor in determining the onset of phase separation and by mixing different ratios of surfactants the ability to tune this phase separation concentration was shown. Dilute solutions of these mixtures well below their respective phase separation concentration were then deposited onto glass substrates via a drop cast or inkjet printer method. The surfactant/polyelectrolyte film composites left after drop evaporation ranged from an amorphous film to nodular like structures. The ability to order/structure actives onto a surface could alter active adhesion and surface roughness properties of the film. This change in surface property could consequently affect antimicrobial performance.

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