In this thesis, a polymeric interphase was developed in order to improve the mechanical properties of glass/polyepoxide model system. The polymeric interphase was composed of sol-gel active hybrid inorganic/organic diblock and gradient copolymers between the glass and polyepoxide interface was introduced in order to enhance the interfacial adhesion between both phases. The design principle of the polymeric interphase was inspired by the tendon-to-bone insertion site, which links to mechanically different tissues. The mechanism of the enhancement of the interfacial adhesion relies on to chemical and physical attachment of the polymeric precursor to both phases. For this purpose, a series of hybrid inorganic/organic copolymers with block and gradient microstructures were synthesized by employing CDTSPA mediated RAFT polymerizations in 1,4-dioxane. The hybrid inorganic/organic copolymers were composed of masked HEMA (THP–HEMA) as epoxy compatible and TESPMA as glass surface compatible component. The synthesis of P(THP–HEMA)-PTESPMA diblock copolymers was accomplished by using a THP–HEMA based MacroCTA approach. This two-step MacroCTA approach yielded well-defined diblock copolymers with narrow MWD and three different TESPMA block lengths. To synthesize well-defined gradient copolymers composed of THP¬–HEMA/TESPMA, the copolymerization kinetics of the given comonomer system was investigated in detail in order to gain detailed information over copolymerization kinetics in batch. In addition, the reactivity ratios were estimated by using a LSNF as well as KTM and EKTM, giving reactivity ratios for both monomers close to one. According to these investigations, the batch copolymerization of THP-HEMA/TESPMA yields exclusively ideal random copolymers. To overcome this limitation, the synthesis of gradient copolymers was accomplished by using a semi-batch forced gradient approach, in which a mixture of THP–HEMA was continuously feeded with 1M TESPMA solution. Due to the inherent reactivity of the comonomers, the steepness of the gradient microstructure could be altered by changing the TESPMA feeding to higher feeding rates. The semi-batch forced gradient approach enabled the preparation of well-defined gradient copolymers with reasonable narrow MWDs. In addition, the semi-batch forced gradient approach give rise to a greater variety of gradient compositions profiles as well as is not limited to a specific comonomer pair with appropriated reactivity ratio as compared to a spontaneous gradient approach. Due to the sol-gel active Si-OCH2CH3 motifs, the spontaneous formation of silica networks was observed in bulk. Thus, the polymeric precursors were stored in anhydrous THF in order to inhibit the spontaneous gelation of the Si-OCH2CH3 motifs. Next, the synthesized block copolymers with three different TESPMA block lengths and two gradient copolymers with diverse gradient microstructures were employed as polymeric precursor to fabricate sol-gel derived hybrid films on glass substrates. The formation of hybrid films on the glass substrates was accomplished by using a base and acid mediated sol-gel grafting-onto spin-coating approach. The former base catalyzed process yielded hybrid films with film thicknesses from 100 to 300 nm. Notably, the hybrid film thicknesses decreased upon treatment with methanolic 0.1M PTSA solution in order to cleave the THP groups from the hybrid film surface. These observations are attributed to shrinkage of the hybrid films upon post-crosslinking of non-reacted Si-OH motifs as well as evaporation of residual solvent. In general, the film thickness could be altered by using precursor with a higher incorporated TESPMA fraction or longer TESPMA block length. To further prove the structural identity of the hybrid films, IRRAS and XPS spectra were recorded. These studies revealed that pedant THP groups were successfully cleaved upon treatment with methanolic PTSA solution. Lastly, a custom-built glass slide-model system was developed, wherein two coated glass slides were stitched with a bisphenol A glycidyl ether-based epoxy resin together. To prove the micromechanical properties of such a model system, mode I tensile tests were conducted and compared with a reference test sample. Based on the experimental data of this tests, the interfacial adhesion strength was relatively increased between 11.9% and 51.1%. The relative increase of the adhesion strength was mainly governed by the hybrid films thicknesses and grafting densities. Thus, hybrid films with a film thickness of ≤ 100 nm and a rather low grafting density result in a stronger interfacial adhesion as compared to thicker hybrid films with a high grafting density. These observations are presumably attributed to an insufficient interpenetration of the PHEMA chains into epoxy resin due to a high chain density. Interestingly, the composition of the polymeric precursor as well as film composition had no crucial impact on the strengthening mechanisms on the nanometer-scale. Following these findings, the hypothesis that a gradient-like macromolecular interphase on a nanometer-scale is highly desirable in order to maximize the interfacial adhesion is not valid. However, these observations might alter by approaching thick hybrid films of ≥ 1000 nm, in which the structural differences of the individual hybrid films are more pronounced. Thus, further experiments should focus on the thicker films with a higher level of film inhomogeneity and spatial resolution. Most likely, such micrometer thick films reveal different film characteristics as compared to the nanometer thick films and the strengthening mechanism is more dominated by structural factors as well as by the inherent mechanical properties of the polymeric interphase. In conclusion, the introduction of macromolecular interphase in a composite-like glass-polyepoxide system has an immanent impact on the mechanical properties. According to the mode I tensile tests, a nanometer thick polymeric interphase composed of block and gradient inorganic/organic copolymers results in an increased interfacial adhesion, due to physical and chemical attachment of tethered polymer chains to both phases. The adhesion between both phases is directly related to the interpenetration of the PHEMA chains into the epoxy resin and thus, a high interfacial adhesion is accomplished by a high level of interpenetrated PHEMA chains. To achieve this, it is advantageous to fabricate thin hybrid films of ≤100 nm and rather low grafting densities of 0.11 chains nm–2. These requirements are sufficiently accomplished by using diblock inorganic/organic copolymers as precursors.
