The External Walls Of The Building Mechanism Of The Dirt And Cleaning Experiments

The large-scale infrastructures, especially the buildings, have being constructedconstantly with the fast development of Chinese economy in recent years. The decorationof the outside wall of these buildings will inevitablely utilize various materials, includingporcelain slice, glass, aluminum board, stone material, stainless steel, coating and so on.As time goes on, the materials of the outside wall on the buildings exposed in theatmosphere will suffer various devastation, including shined by the ultraviolet ray, beatenby weathers, adhered by dust and so on. On one hand, it will shorten the life of thebuildings. On the other hand it will destroy the scenery of the buildings. Therefore, thework has already become highlight that a lot of scholars have being studied on thewashing and keeping clean of the outside wall of these buildings. The author finds thewashing technology about the surface of outside wall of buildings is mature after doing alarge amount of search in the literature on the washing technical field of the surface ofoutside wall of buildings. However, there are few researches on the pollutant how toadhere to the surface of the outsider wall of the buildings and its influencing factors andthe detection of the result of washing. In addition, people always adopt the method oftreament after poulltion rather than the method of prevention before poulltion of theoutside wall of the buildings nowadays. This paper studies the dust adhesion to the surfaceof the outside wall of the buildings, according to surface physicochemistry, interfacechemistry and clean technology theory and so on. The author uses optics microscopesystem to make analysis and research of dust on the surface of glass and ceramic tile, andthe main conclusions of the study are as follows:(1) On the basis of information from literature, the author sums up that adhesionmechanism of pollutant on the surface of the outside wall of the buildings are mainlymechanical, physical and chemical adhesion. Mechanical adhesion is mainly caused by thefriction arised from the surface roughness of surface materials of the outside wall of thebuildings. The force of physical adhesion comprises Van der Waals forces made up ofdipole force, induction force and dispersion interaction energy, electrostatic attractionforce, hydrogen-bond force and capillary force. The force of chemical adhesion comprisesionic bond and covalent bond, and generally they are coexistent.(2) The adhesion influencing factors of pollutant of surface materials of the outsidewalls consist of the man-made factor, machine factor (the surface materials of buildingsoutside wall and pollutant) and environmental factor. The human factor mainly containsthe production of air pollutants and the mistake of management. The factor of surfacematerials of outside wall of buildings contains the surface roughness, surface hydrophilicand hydrophobic capability and the chemical composition. The factor of pollutant (the research object of the dissertation is dust) contains the dust shape, size, wet ability,adhesion charge and so on.(3) The dissertation discusses decontamination mechanism of anti-fouling agent tothe surface materials of of outside wall of buildings, including paraffinaceous antifoulingchemical, latex antifouling chemical, organic silicon antifouling chemical andfluorine-containted antifouling chemical and self-cleaning anti-fouling materials. Theprecondition of these antifouling chemical is waterproof or water-repellent, and thesecondary precondition is ventilation and penetrative. The fluorine-containted anti-foulingchemical and the self-cleaning anti-fouling materials is the tendency of development.(4) The dissertation tests the relative easiness grade of removal of dust particles onthe glass infused by several chemical reagents surface. Whether the use of airflow force orthe use of water force to remove dust particles from the glass surface, the removalefficiency of dust particles of the glass infused by dilute ammonia surface all are thehighest. The amount of dust particles on the glass without infusing any chemical reagentssurface is the fewest, but it is the most difficult to remove from the surface. It indicatesthat it is beneficial to adhere to the glass surface for dust particles when the glass surfaceis infused by chemical reagents. No chemical reagents adhesion to the glass surface of arelatively small number of particles of dust that after the glass surface contaminants wouldbe beneficial to the glass surface dust adhesion can be difficult to remove these dustparticles, but not the translucent glass (very small percentage of dust particles). Therefore,without pre-judice to the nature of the glass, using alkaline better handle glass surface.(5) The dissertation tests anti-fouling capability of the surface of the ceramic tilesspreaded fluorocarbon surfactant. The anti-fouling grade of the surface of the ceramic tilesspreaded fluorocarbon surfactant is higher than the anti-fouling grade of the surface of theceramic tiles without spreading fluorocarbon surfactant, whether the pollutant is rust orblack ink.(6) The pattern that the surfactant adsorbs on different solid surface is different. Thisdissertation puts forword models of surfactant adsorb on different solid surface, which cansuitably explain the adsorption processes and conformation.