Bottlebrush polymers are intriguing topologies that have become more significant in various applications, including drug delivery, elastomers, photonic crystals, anti-fouling coatings, nanoporous materials, and electronic and transport substrates. Polymeric side chains are tightly grafted to a polymer backbone in these macromolecules. Bottlebrush polymers' densely bonded structure causes steric repulsion between nearby polymer chains, leading them to exhibit a chain-extended conformation. Even though these extraordinary macromolecules have several uses, the transformational promise of the bottlebrush polymer architecture has yet to be realized due to the difficulty in synthesizing large molecular weight bottlebrush polymers. This dissertation illustrates the ability of the optimized grafting-through strategy to create controlled supramolecular polymeric networks (SPNs) and different types of topologies, including block copolymers and tapered bottlebrush polymers. We show that the optimized synthesis of bottlebrush polymers using a direct-growth approach results in a controlled product and monomodal size exclusion chromatography (SEC) peaks. The optimization of the direct-growth approach depends on two factors: monomer type and percentage of monomer to polymer conversion in the reversible-deactivation radical polymerization (RDRP) step. Moreover, performing ring-opening metathesis polymerization (ROMP) initiated by Grubbs 3rd generation catalyst (G3) on a norbornene functionalized macromolecules allows for creating polymers with bulky side chains. This strategy was implemented to create methylated, acetylated, and native poly(β-cyclodextrin) that reached a degree of polymerization of 150 and molecular weights > 150 kg/mol. These results were 10-fold higher than the reported method using atom transfer radical polymerization (ATRP) with β-cyclodextrin functionalized with methacrylate group. Furthermore, multiple macromonomers were prepared using ATRP and photoiniferter polymerization that are functionalized with norbornene. These macromonomers were used in the following ROMP reaction to result in multiple series of amphiphilic bottlebrush block copolymers and tapered bottlebrush polymers. The surface tension measurements on the self-assembled amphiphilic bottlebrush block copolymer series in water revealed an ultralow critical micelle concentration (CMC), 1-2 orders of magnitude lower than its linear counterpart. Combined with coarse-grained molecular dynamics simulations, fitting small-angle neutron scattering traces (SANS) allowed us to evaluate solution conformations of micellar nanostructures for self-assembled macromolecules. Furthermore, the tapered bottlebrush polymer series SANS traces were collected to investigate their molecular arrangement in dilute solution. For the first time, summation scattering models describing both bottlebrush polymer shape and side chain polymer conformations were utilized. Using these models, we extracted physical parameters of the polymers, including bottlebrush radius and length as well as side chain excluded volume parameter and correlation length. / Doctor of Philosophy / Bottlebrush polymers are intriguing topologies that have become more significant in a variety of applications, including photonic crystals and nanoporous materials. In these macromolecules, polymeric side chains are densely grafted to a polymer backbone which causes steric repulsion between nearby polymer chains. However, even though these extraordinary macromolecules have several uses, the transformational promise of the bottlebrush polymer architecture has yet to be realized due to the difficulty in synthesizing large molecular weight bottlebrush polymers. This dissertation illustrates the ability of the optimized grafting-through strategy to create controlled supramolecular polymeric networks (SPNs) and different types of topologies, including block copolymers and tapered bottlebrush polymers. This dissertation shows that the optimized synthesis of bottlebrush polymers using direct-growth approach results in a controlled synthesis. The optimization of the direct-growth approach depends on two factors: monomer type and percentage of monomer to polymer conversion in creating the macromonomer step. In addition, performing ring-opening metathesis polymerization (ROMP) initiated by Grubbs 3rd generation catalyst on a norbornene functionalized macromolecules allows for creating polymers with bulky side chains. This strategy was implemented to create methylated, acetylated, and native poly(β-cyclodextrin) that reached a degree of polymerization of 150 and molecular weights > 150 kg/mol. Multiple macromonomers were prepared using ATRP and photoiniferter polymerization that are functionalized with norbornene. These macromonomers were used in the following ROMP reaction to result in multiple series of amphiphilic bottlebrush block copolymers and tapered bottlebrush polymers. The surface tension measurements on the self-assembled amphiphilic bottlebrush block copolymer series in water revealed an ultralow critical micelle concentration (CMC). In addition, fitting of small-angle neutron scattering traces (SANS) allowed us to evaluate solution conformations for micellar nanostructures for self-assembled macromolecules. Furthermore, the tapered bottlebrush polymer series SANS traces were collected to investigate their molecular arrangement in dilute solution. Finally, for the first time, models were used to extract physical parameters of the polymers, including bottlebrush radius and length as well as side chain excluded volume parameter and correlation length.

La bioinspiration consiste à analyser les systèmes naturels qui se sont adaptés parfaitement à leurs environnements pour développer des solutions ingénieuses. Ce projet de thèse aborde la thématique de la lubrification articulaire dans le but de développer un traitement contre l'ostéoarthrite (OA). Nous nous sommes inspirés des articulations synoviales, systèmes tribologiques très performants grâce aux interactions synergiques entre la structure unique du cartilage et les molécules lubrifiantes (ML) du fluide synovial (SF). Cependant, lors de l'OA des mécanismes inflammatoires et d'érosion mécanique aboutissent à la dégénérescence progressive du cartilage et la dégradation spécifique des ML du SF (aggrécane et lubricine). Des mimes des ML du SF ont été synthétisés reprenant leur structure particulière dite en écouvillon moléculaire (BB), structure responsable de la lubrification. Des tests tribologiques (SFA, tribomètre) ont montré que les BB garantissent à la fois une faible friction et une résistance à l'usure sur des surfaces dures de mica. Ceci est dû à la présence, sur nos EM, de groupements d'ancrage spécifiques assurant l’adsorption sur la surface de mica et à la formation d'enchevêtrements et d’interactions intermoléculaires avec l'acide hyaluronique de haut poids moléculaire, composant essentiel du SF. Des mimes de cartilage à base d'hydrogels de chitosane multicouches ont été également réalisés reprenant les principales propriétés architecturales du cartilage. En combinaison avec nos EM, ces hydrogels, matériaux poroélastiques fragiles, sont capables d’être lubrifiés avec une friction dans la gamme physiologique et une nette amélioration de leur usure / Bioinspiration consists in the design of materials inspired by biological systems which have developed ingenious solutions to suit their environment. This project deals with bioinspiration for joint lubrication and in particular for the development of treatments for patients suffering from osteoarthritis (OA). To do so, we took our inspiration from joints which are amongst the most efficient aqueous tribological systems. Their unique properties arise from the complex synergistic interactions between cartilage structure and the lubricant macromolecules of the synovial fluid (SF). However, during OA, inflammatory mechanisms as long as mechanical erosion result in the degeneration of cartilage and lubricant macromolecules (aggrecan and lubricin). Polymeric mimes of the SF have been synthesized based on the bottle-brush (BB) architecture of LUB and AGG which is responsible for the joint lubrication. Tribological tests (SFA, tribometer) showed that BB polymers provided mica surfaces with a low friction and a wear protection up to several megapascals, typically in the range of natural joints. This wear protection was essentially due to the incorporation of anchoring groups specific to mica tribopairs on the BB polymers and the intermolecular bridging and entanglements emerging between BB polymers and high molecular weight HA, another main SF component. Cartilage mimes composed of multilayered chitosan hydrogels were designed to mimic the basic features of cartilage. Along with our BB polymers, the hydrogels, which are poroelastic and fragile materials, provided a low friction and a great decrease of wear

La friction entre les surfaces mobiles de l’organisme peut être un problème difficile à résoudre, notamment dans les pathologies dégénératives comme l’arthrose ou la sécheresse oculaire. Malgré le développement de nombreux produits pharmaceutiques, les matériaux actuellement utilisés pour protéger les tissus blessés et les dispositifs biomédicaux contre l'usure par frottement sont encore limités dans leurs performances. Il existe un besoin urgent de matériaux injectables capables de protéger ces tissus et dispositifs afin de prolonger leur durée de vie et de traiter efficacement des maladies dégénératives. Parmi les innovations de la dernière décennie, les polymères à structure dite « en brosse » (BBs) se sont révélés prometteurs pour amoindrir les problèmes de friction et d'usure. Inspirés de l’architecture spécifique du protéoglycane 4, l'un des principaux composants lubrifiants du cartilage, les macromolécules BBs sont constituées d’un squelette linéaire et de chaînes latérales formant une brosse dense pouvant maintenir de l’eau sous une pression élevée. Les différentes structures des BBs, selon le squelette et leurs chaînes latérales, conduisent à plusieurs caractéristiques morphologiques et propriétés tribologiques intéressantes dans l’ingénierie tissulaire. Bien que leurs propriétés lubrifiantes aient été prouvées dans plusieurs études, les BBs n’ont à ce jour que peu d’applications. D’une part, la corrélation entre leur structure et leurs propriétés physicochimiques n’est pas encore clairement établie. D’autre part, il manque encore des études relatives à l’efficacité des BBs sur de vrais tissus. Pour pallier ce problème, notre projet vise à caractériser les propriétés physicochimiques et tribologiques des BBs sur différents types de surfaces en fonction de leur structure. La longueur du squelette, la densité de greffage et l’addition du groupe d’ancrage sont les 3 variables principales étudiées dans ce projet. La lubrification ainsi que d’autres propriétés importantes des BBs ont été évaluées sur les surfaces molles des cartilages, des yeux et des lentilles en contact. Les tests tribologiques ont été menés en utilisant un appareil à force de surface (SFA) via l’association du protocole classique et avancé qui l’adapte aux surfaces testées. A côté de la tribologie, l’affinité cinétique, la toxicité, les propriétés antisalissure et anti-inflammatoire des BBs sur les interfaces ont aussi été étudiées dans ce projet via les techniques de LigandTracer et de microscope fluorescent. / Friction between the body's moving surfaces can be a difficult problem to solve, particularly in degenerative pathologies such as osteoarthritis or dry eye. Despite the development of numerous pharmaceutical products, the materials currently used to protect injured tissues and biomedical devices against frictional wear are still limited in their performance. There is an urgent need for injectable materials capable of protecting these tissues and devices in order to extend their life and effectively treat degenerative diseases. Among the innovations of the last decade, polymers with a so-called "brush structure" (BBs) have shown promise in reducing friction and wear problems. Inspired by the specific architecture of proteoglycan 4, one of the main lubricating components of cartilage, BBs macromolecules consist of a linear backbone and side chains forming a dense brush capable of holding water under high pressure. The different structures of BBs, depending on the backbone and their side chains, lead to several morphological features and tribological properties of interest in tissue engineering. Although their lubricating properties have been proven in several studies, BBs have few applications to date. On the one hand, the correlation between their structure and physicochemical properties has not yet been clearly established. On the other hand, studies on the effectiveness of BBs on real tissues are still lacking. To overcome this problem, our project aims to characterize the physicochemical and tribological properties of BBs on different types of surfaces, depending on their structure. Backbone length, graft density and anchoring group are the 3 main variables studied in this project. Lubrication and other important properties of BBs were evaluated on the soft surfaces of cartilages, eyes and contact lenses. Tribological testing was carried out using a Surface Force Apparatus (SFA) via a combination of the classic and advanced protocol, adapting it to the surfaces tested. Alongside tribology, the kinetic affinity, toxicity, anti-fouling and anti-inflammatory properties of BBs on interfaces were also studied in this project via LigandTracer and fluorescent microscopy techniques.