Ce travail de thèse a porté sur l’élaboration de nanomatériaux hybrides de type nano-câbles fonctionnels, composés de polymères covalents et de molécules auto-assemblées. L’approche «bottom-up» adoptée repose sur des processus uniquement physiques, à savoir la nucléation hétérogène, la cristallisation et la gélification thermo réversible. Deux systèmes hybrides ont été élaborés et étudiés: le premier est composé de molécules de tetra-2-éthylhexanoate de bicuivre (CuS8) auto-assemblées en filaments, lesquels sont encapsulés au sein des fibrilles de polystyrène isotactique (iPS). Nous avons montré au travers de différentes études (DSC, DNPA,SQUID, EXAFS et IR-TF) que leur encapsulation permet non seulement de les stabiliser mais également de modifier leur comportement antiferromagnétique. Le deuxième système a consisté à des fibrilles de poly(alkylthiophène)s (P3AT), emmaillotées au moyen de molécules diamides (BHPB-10) capables de s'assembler en nanotubes. En plus des études de la morphologie et de la structuration par TEM et UV-Vis,nous avons étudié les propriétés de conductivité du système hybride P3BT/BHPB-10 en C-AFM. Nous avons montré qu’il est effectivement possible de réaliser des nano-câbles semi-conducteur gainés. / This thesis deals with new hybrid nanomaterials of functional nanocable-like structures, consisting of covalent polymers and self-assembled molecules. The «bottom-up» approach adopted for the elaboration is based only on physical processes such as heterogeneous nucleation, crystallization and thermoreversible gelation. This original approach allowed us to easily prepare two functional nanocables: the first consisted of bicopper tetra-2-ethylhexanoate (CuS8) molecules self-assembled on filaments which are encapsulated within isotactic polystyrene (iPS) fibrils. We proved throughout different studies (DSC, SANS, SQUID, EXAFS and FT-IR) that the encapsulation allows one to get stable filaments, and particularly to modify their antiferromagnetic behavior as well. The second system constituted of poly(alkylthiophene)s fibrilles (P3AT), sheathed by diamides molecules (BHPB-10) self-assembled on nanotubes. Besides the morphological and the structuration studies (TEM and UV-Vis), we investigated the conductivity of the hybrid system P3BT/BHPB-10 by C-AFM. Results showed the possibility to obtain sheathed semi-conducting nano-cables.

Optically transparent carbon based nanomaterials including graphene and carbon nanotubes(CNTs) are promising candidates as transparent conductive electrodes due to their high electrical conductivity coupled with high optical transparency, can be flexed several times with minimal deterioration in their electronic properties, and do not require costly high vacuum processing conditions. CNTs are easily solution processed through the use of surfactants sodium dodecyl sulfate(SDS) and sodium cholate(SC). Allowing CNTs to be deposited onto transparent substrates through vacuum filtration, ultrasonic spray coating, dip coating, spin coating, and inkjet printing. However, surfactants are electrically insulating, limit chemical doping, and increase optical absorption thereby decreasing overall performance of electrodes. Surfactants can be removed through nitric acid treatment and annealing in an inert environment (e.g. argon). In this thesis, the impact of surfactant removal on electrode performance was investigated. Nitric acid treatment has been shown to p-dope CNTs and remove the surfactant SDS. However, nitric acid p-doping is naturally dedoped with exposure to air, does not completely remove the surfactant SC, and has been shown to damage CNTs by creating defect sites. Annealing at temperatures up to 1000°C is advantageous in that it removes insulating surfactants. However, annealing may also remove surface functional groups that dope CNTs. Therefore, there are competing effects when annealing CNT electrodes. The impacts on electrode performance were investigated through the use of conductive-tip atomic force microscopy, sheet resistance, and transmittance measurements. In this thesis, the potential of graphene CNT composite electrodes as high performing transparent electrodes was investigated. As-made and annealed graphene oxide CNT composites electrodes were studied. Finally, a chemical vapor deposition grown graphene CNT composite electrode was also studied.

In this work, scanning multiprobes microscopes were used to study the physical properties of biological, vitreous and ceramics samples. In particular, we have used three different scanning probe microscopy techniques to the study the samples. At first, an atomic force microscope was used to evaluate the mechanical properties of macrophages due to cell adhesion to an extracellular matrix and to study the changes in DNA molecules conformation treated with thymol and adsorbed onto a mica surface modified by poly-L-lysine. The results of these studies show that the cytoskeleton-mediated cell-matrix interactions directly affect biomechanical events in cells by modifying physical properties of the cytoskeleton and that the modification of mica surface using poly-L-Lysine provides a strong and firm bond with DNA. This strong fixation of DNA, allows the study of DNA conformational change on mica when interacting with tymol. The atomic force microscope was also used in studies of laser induced thermal expansion in commercial phosphate glasses. The ability of this technique to detect nanoscale surface deformations and the good agreement between theoretical and experimental results show the potential of this technique to study the amplitude and the dynamic of thermal effects in solid materials. In another study, conductive atomic force microscopy was used to analyze electrical properties of barium titanate semiconductor ceramic and their correlation with specific topographic features of the sample. Finally, using the scanning near-field optical microscopy, we studied interactions between cells and gold nanoparticles, without the need of fluorescent labeling on the nanoparticles, with high spatial resolution. During the presentation of these studies the challenges and necessary instrumentation for their realization was discussed. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho, microscópios de varredura multi-sondas foram utilizados para o estudo de propriedades físicas de amostras biológicas, vítreas e cerâmicas. Em especial, usamos três diferentes técnicas de microscopia de varredura por sonda no estudo destas amostras. Primeiramente, um microscópio de força atômica foi usado para avaliar os efeitos na mecânica da membrana de macrófagos, verificando a interferência da adesão celular por uma matriz extracelular. Em seguida, estudamos as mudanças de conformação de moléculas de DNA tratadas com Timol e adsorvidas sobre uma superfície de uma mica modificada por poli-L-lisina. Os resultados destes estudos implicam que as interações célula-MEC mediada pelo citoesqueleto afetam diretamente os eventos biomecânicos das membranas, modificando as propriedades físicas do citoesqueleto celular, e que a modificação da superfície da mica utilizando poli-L-Lisina proporciona uma ligação forte e firme com o DNA. Esta forte fixação do DNA, permitiu o estudo da mudança conformacional do DNA na mica quando interagindo com o timol. O microscópio de força atômica também foi usado para realizar de estudos da expansão térmica em vidros fosfatos comerciais, induzida por um laser. A capacidade desta técnica de detectar deformações superficiais em nano-escala e a boa concordância dos resultados teóricos e experimentais mostra o potencial desta técnica para o estudo da amplitude e dinâmica de efeitos térmicos em materiais sólidos. Num outro estudo, a microscopia força atômica condutora foi usada para a análise de propriedades elétricas de cerâmicas de titanato de bário semicondutor e suas correlações com características topográficas específicas da amostra. Por fim, estudamos interações entre células e nanopartículas de ouro, com o uso da microscopia de varredura em campo próximo, sem a necessidade de marcação fluorescente nas nanopartículas e com alta resolução espacial. Durante a apresentação de cada um destes estudos foi discutido os desafios e parte da instrumentação necessárias para a realização dos mesmos.