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TY  - THES
AU  - Jeschenko, Pascal Max
TI  - Surface modification with selectively adsorbing polymers
PB  - RWTH Aachen University
VL  - Dissertation
CY  - Aachen
M1  - RWTH-2023-10665
SP  - 1 Online-Ressource : Illustrationen
PY  - 2023
N1  - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2024
N1  - Dissertation, RWTH Aachen University, 2023
AB  - In this thesis, tailor-made polymers acting at the solid-liquid interface are investigated. The focus of this work is the steric stabilization of nanoparticles in solution through selectively adsorbed polymers. Commonly, competing processes occur during dispersion formulation, i.e., the formation of inactive polymer aggregates. Here, affinity to the surface is enhanced by improving the solvophilicity of the surface-active building block, thus increasing the amount of adsorbed material. First, a modular, computer-aided design process for dispersing agents based on glycidyl methacrylate (GMA) copolymers is presented. As a case study, the development of a dispersant for a specific carbon black is conducted. The surface chemistry of the pigment is characterized in order to reveal potential surface-affine groups for simulation and rational design. Small molecule model compounds, resembling GMA repeating units after modification with affine groups are synthesized, analyzed with regard to their solubility in water and propylene glycol monomethyl ether acetate (PMA) and investigated for their affinity towards carbon black. Coarse grain simulations of polymers containing different affine groups, which allow for the preselection of promising, well stabilizing candidates, are conducted. For use in organic solvents, statistical, gradient and block copolymers from GMA and n-butyl methacrylate (nBuMA) are synthesized via group transfer polymerization and subsequently modified with three chosen pigment-affine groups. Carbon black dispersions are prepared following either self-assembly or beadbeating-based approaches. The pigment affinities and stabilizing properties of the synthesized dispersants are quantified and analyzed with respect to the influence of polymer structure and attached affine group. Water-based carbon black dispersions are prepared using oligo(ethylene glycol) methacrylate-containing polymers. Here, the aggregation behavior in solution and dispersing agent performances of linear and comb-type polymers are characterized and compared. Next, a new class of dispersing agents based on double hydrophilic p(N-vinylamide) is investigated. Through improved hydrophilicity, the aggregation of polymer chains is suppressed, allowing for the development of superior dispersants. Surface adsorption occurs through selective interactions between polymer and pigment instead of the hydrophobic effect. Copolymers of N-vinylformamide (NVF) and -acetamide (NVA) are synthesized and partially hydrolyzed under acidic conditions. The generated poly(N vinylamine)s are functionalized with poly(ethylene glycol) sidechains to further improve the stabilizing properties. The superior capabilities of the polymers to stabilize the solid-liquid interface are demonstrated at the example of aqueous carbon black dispersions. Moreover, the influence of pH on the dispersions’ properties is explored, as well as the solution behavior of the polymers under acidic and basic conditions. Lastly, a hydrophilic soil-release coating intended for the use in graffiti prevention is developed. The coating is water-based and environmentally benign, consisting of supramolecular crosslinked hydrogels made from p(N-vinylamine)s with pendant guanidine groups. Long chain N-vinylamide polymers are synthesized and hydrolyzed. Different methods for the introduction of guanidine moieties are compared. The obtained polymers are applied to glass, concrete, ceramic and acrylic paint substrates, stained with permanent marker and spray paint and subsequently cleaned with water. An in-depth study of structure-property relationships regarding the (in)visibility, cleaning effects, durability and weathering resistance of the coatings is conducted.
LB  - PUB:(DE-HGF)11
DO  - DOI:10.18154/RWTH-2023-10665
UR  - https://publications.rwth-aachen.de/record/973215
ER  -