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    Synthesis and characterization of branched polyglycerol surfactants
    (2024) Moilanen, Eric; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Evenäs, Lars; Bordes, Romain; Bilén, Frida
    Polyglycerol surfactants have emerged as a promising renewable alternative to fossil based polyethylene glycol surfactants. The polyglycerol head group offers greater structural variability and possibility for functionalization. In order to facilitate the transition to renewable nonionic surfactants, a deeper understanding of the structure-property relationship, particularly regarding branching, is essential. To this end, two polyglycerol structures with different degrees of branching were synthesised through a series of chemical reactions. These structures were then esterified with carboxylate tails of varying lengths and analyzed by tensiometry, interfacial rheology and quartz crystal microbalance with dissipation monitoring. The results indicated that enlargement of the branched head group significantly influences the surfactants self-assembly and the air-water interfacial rheology. QCM-D analysis showed that the branched head group binds very strongly to hydrophilic surfaces, likely due to its hydroxylated nature.
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    Advancing Near-Term Quantum Computing for Chemistry: Multireference-State Error Mitigation
    (2024) Zou, Hang; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Rahm, Martin; Rahm, Martin
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    Preparation and Characterization of TEMPO-CNFs/Cellulose Acetate Composite Films: An Investigation into New Biobased Composites
    (2024) Chen, Hongrun; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Westman, Gunnar; Isogai, Akira
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    Comprehensive analysis of PTFE distribution in gas diffusion layers using advanced ex-situ and in-situ characterization techniques
    (2024) RAVI SANKAR, SIVA BALAGANESH; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Martinelli, Anna; Ringström, Magnus; Schulz, Dylan
    The performance and longevity of Proton Exchange Membrane Fuel Cells (PEMFCs) are critically dependent on the properties of the gas diffusion layer (GDL). This study investigates the hydrophobic treatment using the dip coating method on two types of GDLs, namely dry-laid and wet-laid, using polytetrafluoroethylene (PTFE) at target concentrations of 5 wt%, 20 wt%, and 50 wt%. The distribution of PTFE across the thickness and surface of the GDLs is characterized to understand its impact on water management and gas transport properties. The effectiveness of the hydrophobic treatment is evaluated both ex-situ via contact angle measurements and in-situ by limiting the current density to assess oxygen transport resistance. Additionally, advanced characterization techniques, including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Raman Spectroscopy, are employed to provide a detailed analysis of PTFE distribution, correlating these findings with the GDL’s performance in operating PEMFCs. **Key findings** reveal that while increased PTFE concentration improved hydrophobicity and water management, excessive PTFE loading led to pore blockage, negatively impacting oxygen transport resistance. The wet-laid GDL demonstrated more uniform PTFE distribution and higher transport resistance compared to the dry-laid GDL. These insights emphasize the importance of balancing PTFE concentration to optimize both water management and gas diffusion in PEMFCs.
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    Polyelectrolyte brushes on porous carbon electrodes for protein capture and electrochemical release
    (2024) Bång, Elin; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Dahlin, Andreas; Ferrand-Drake del Castillo, Gustav; Olsson, Oliver
    Biopharmaceuticals are medical drugs produced from biological components. Necessary steps in the manufacturing includes isolation and purification of biomolecules, for which chromatography is a common technique. However, it requires harmful elution chemicals, that can affect the desired product. To achieve a more efficient and non-invasive way for biopharmaceutical production, there is an interest of developing new methods for purification of biomolecules. The electrode surface of Nyctea Technologies utilizes polyelectrolyte brushes responsive to pH-stimuli. By alternating pH, or by electric signals, the brushes can switch between charged and neutral state. This enables interactions that allows the brushes to reversible capture and release biomolecules like proteins. The polymer coating has previous been applied to gold coated steel surfaces. The aim of this project was to investigate alternative substrate materials with the purpose to improve the protein binding capacity of the electrodes. Displaying attractive properties such as high chemical stability and electrical conductivity, having high specific surface area, and high availability at low cost, porous carbon electrode materials was further explored. The synthesis of poly(methacrylic acid) (PMAA) brushes was performed on reticulated vitreous carbon (RVC) and on carbon felt. By thermogravimetric analysis (TGA) the polymer amount on the coated materials could be quantified. It was confirmed to be PMAA on the felt, while the RVC showed no clear signs of attached polymer. The protein binding capacity of the carbon electrodes was evaluated by pH controlled catch and release of protein, using bovine serum albumin (BSA). The RVC was unsuccessful while the felt preformed better, and was chosen to be further developed as an electrode material. The carbon felt electrodes was assembled in capsules and connected to a chromatography system. Results made clear that protein was captured by the electrodes, and protein release was possible both by pH elution and by electrochemistry, making the carbon felt a promising candidate for future research.