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Título: INFLUENCE OF CAPILLARY CONDENSATION IN NANOSCALE FRICTION
Autor: ROBERT RONALD MAGUINA ZAMORA
Colaborador(es): RODRIGO PRIOLI MENEZES - Orientador
Catalogação: 27/JUN/2005 Língua(s): PORTUGUESE - BRAZIL
Tipo: TEXT Subtipo: THESIS
Notas: [pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio.
[en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio.
Referência(s): [pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=6648&idi=1
[en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=6648&idi=2
DOI: https://doi.org/10.17771/PUCRio.acad.6648
Resumo:
In this work, the procedures developed to the calibration of the AFM photodetector and cantilevers for lateral force measurements in our AFM is presented. A Matlab code that controls the microscope allows the study of the influence of the normal force on the lateral one. A second Matlab code was developed in order to study the adhesion forces in an automated way. We present and discuss the influence of the surface free energy on the friction and adhesion forces. In this work, the lateral forces were measured at hydrophilic and hydrophobic surfaces. It was observed that the nano asperities may form single asperity contacts described by the Hertz model as well as multi-asperity type of contacts described by the Greenwood model. The nanoasperity contact may be controlled by the wettability and ambient relative humidity. It is seen that the capillar formed between the tip and the surface influences the tip-surface normal force and the friction forces due to the dissipation of energy caused by the drag or brake of the capillar meniscous. The effect of capillary condensation kinetics was studied as well. It is shown that the surface wettability is determinant to the energy dissipation mechanism in nanoscale. The influence of the surface wettability on the friction coefficient is presented. The observed correlation between the friction coefficient and contact angle enhances the influence of the surface wettability and its kinetics in the friction forces at nanoscale.
Descrição: Arquivo:   
COVER, ACKNOWLEDGEMENTS, RESUMO, ABSTRACT, SUMMARY AND LISTS PDF      
CHAPTER 1 PDF      
CHAPTER 2 PDF      
CHAPTER 3 PDF      
CHAPTER 4 PDF      
CHAPTER 5 PDF      
CHAPTER 6 PDF      
REFERENCES AND APPENDICES PDF