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Diphenylamine diazonium salt of light , thermal decomposition , and based on a composite of the resin , the self-assembled

Author: ChenJinYu
Tutor: CaoWeiXiao
School: Beijing University
Course: Polymer Chemistry and Physics
Keywords: diazoresin polyelectrolyte complexes photo-decomposition thermo-decomposition self-assembly electrostatic attraction hydrogen-bonding hydrophobic interaction dynamic contact angle
CLC: O621.25
Type: PhD thesis
Year: 2001
Downloads: 230
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Abstract

This dissertation is composed of two parts.In the first part, carbazole-3-diazonium salts (C-3-DS), N-ethyl-carbazole-3-diazonium salts (NEC-3-DS); N-benzyl-carbazole-3-diazonium salts (NBC-3-DS);N-methyl-diphenylamine-2-nitro-4- diazonium salts (MNDDS) and the corresponding resins (the polycondensation product with formaldehyde) were synthesized. The photochemical and thermal decomposition of various diphenylamine diazonium salts in ethanol were studied. It was found that, the major products in photochemical decomposition are their corresponding substituted diphenylamino-4-ethyl ethers while their corresponding diphenylamines were obtained as only one product in the case of thermal decomposition. For the decomposition of MNDDS in water, the decomposition products are identical both in photochemical and in thermal decomposition. The mechanisms of photochemical and thermal decomposition were discussed.Using diphenylamine-4-diazonium-formaldehyde resin (DR) or 2-nitro-N-methyl-4-diazonium -formaldehyde resin (NDR) as polycations, the photosensitive polyelectrolyte complexes were studied with poly (sodium vinylsulfonate) (PSV), poly(sodium-p-styrenesulfonate) (PSS), poly(potassium salt, 3-sulfopropyl acrylate) (PPSA) or poly(potassium salt, 3-sulfopropyl methacrylate) (PPSMA) as polyanions. It was found that the water-insoluble DR-based polyelectrolyte complexes ( i-DR-PEC) were formed in the region of molar ratio less than 1:1 ( chain unit) of polyanions to diazoresins, but the addition of excessive polyanions will dissolve the i-DR-PEC to form water-soluble DR-based polyelectrolyte complexes (s-DR-PEC). The polyanion with flexible longer side-chain or the DR with stronger hydrophobic group exhibits higher ability to dissolve the PEC. It was believed that the hydrophobic interaction between the excessive polyanion molecules and DR-PEC chains plays a key role in the dissolution of i-DR-PEC.The second part focuses on the study of the self-assembly films based on diazoresins. The multilayered ultra-thin films using DR or NDR as polycations and PSS, PVS as polyanions or dyes (Sulfonated Porphyrin(SPP), sulfonated phthalocynine(SPH) , 4,4’-di(sodium styryl-2-sulfonate) biphenyl(DSB)) , as well as charged nanoparticles, soluble single wall carbon nanotube as multianions were fabricated and investigated. In all cases of the above multiplayer films, a linkage conversion from electrostatic bond to covalent bond takes place following the decomposition of -N2+ group when the multilayer films undergo UV irradiation. As a result, the ability of the film against etching from polar solvents increases dramatically. The surface morphology visualized by AFM as well as the regularity of the films studied by XRD was also reported.We found that the diazonium group can form H-bond with phenolic hydroxy and the multilayered film from DR and phenol-formaldehyde resin (PR) was first fabricated. The driving force of self-assembly was verified to be the hydrogen bond attraction from -N2+ group and H-donor with FTIR, and a linkage conversion from H-bond to covalent bond also takes place undergoes UV irradiation. In the case of NDR and PR, a covalently linked ultra-thin multilayer film formed in-situ via layer-by-layer deposition. The UV-vis, XRD, AFM and FTIR show that all of the multilayer films are of high regularity, smoothness and high stability towards polar solvents.The surface nature of the multilayer films from PDDA/PSS, PEI/PSS, DR/PSS, NDR/PSS, DR or NDR itself were explored using dynamic contact angle (DCA) by the wilhelmy plate method. We confirmed that the adjacent layer interpenetration is severe and the re-organization of the components occurs in the deposition process. We also put forward that the hydrophobic interaction is present in all of the self-assembly process and is a key force responsible for the DR and NDR self-adsorption. The washing and drying are prerequisites for the successful fabrication especially in the fabrication with same charged materials.

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