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- PostSelf-assembly behavior in systems containing surfactants and chelating agents(2024) Nero, Emelie; Jacobsson, Frida; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Evenäs, Lars; Velásquez, Josmary; Bordes, RomainCleaning products play a crucial role in effectively maintaining a healthy and hygienic living environment. In all cleaning formulations ingredients like chelating agents and surfactants are essential for the products’ performance. This study investigates the self-assembly of surfactants in the presence of chelating agents and their influence on the physicochemical properties and cleaning efficiency of cleaning formulations. The formulations consist of a nonionic surfactant, a chelating agent and a secondary surfactant. Three amine-based secondary surfactants were evaluated, including an amphoteric surfactant, an amine oxide, and a quaternary ammonium compound (quat). The chelating agents evaluated were L-glutamic acid N,N-diacetic acid tetrasodium salt (GLDA), methylglycine N,N-diacetic acid trisodium salt (MGDA), ammonium citrate and citric acid. The study focuses on how these components affect clouding temperature, viscosity, foaming, wettability, and surface tension. Results show that clouding temperature, viscosity, and foaming are notably impacted by the choice of secondary surfactant and chelating agent, whereas surface tension remains unchanged. Amphoteric surfactants, in particular, reduce the salting-out effect of chelating agents like MGDA and GLDA, likely due to the similarity between their molecular structures. This interaction is hypothesized to lower the critical packing parameter (CPP), leading to smaller, more spherical micelles that increase solubility, raise clouding temperature, decrease viscosity, and improve foaming. These changes could enable higher concentrations of active ingredients, resulting in more concentrated, energy-efficient products with reduced packaging needs. Cleaning performance tests on model soils revealed that formulations combining amphoteric or amine oxide surfactants with GLDA or MGDA were most effective across various surfaces and soil types, especially at higher concentrations of chelating agents. These findings suggest that combining amphoteric surfactants with GLDA or MGDA could lead to the development of more concentrated, sustainable cleaning products.
- PostSynthesis 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, FridaPolyglycerol 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.
- PostAdvancing 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
- PostPreparation 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
- PostComprehensive 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, DylanThe 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.