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Amphiphilic polymers can self-assemble into various structures that show promise as nanocarriers of active substances. Polysiloxane-based block copolymers have features like low glass transition temperature, chain flexibility, high hydrophobicity, and biocompatibility. While amphiphilic diblock copolymers of polysiloxane and poly (ethylene oxide) (PDMS-PEG) have shown spontaneous vesicle formation and reverse liquid crystalline phases in water, there are no reports on making liquid crystalline dispersions like hexosomes and cubosomes, i.e., nanostructured soft materials particles. PDMS-PEG hexosomes and cubosomes are expected to have particular features as compared to those derived from lipids, such as longer hydrophobic and hydrophilic internal domains and, therefore, distinct encapsulation properties. In this work, we aim to explore the self-assembly of our hydrosilanation-synthesized PDMS-PEG into hexosomes and possibly cubosomes in phosphate-buffered saline (PBS) solutions, a physiologically relevant medium for biomedical use. In preliminary experiments, we performed in-house SAXS measurements on highly concentrated samples that confirmed the formation of a reverse hexagonal (H₂) phase in PBS, demonstrating that PDMS-PEG can potentially form hexosomes under physiologically relevant conditions. At lower concentrations, Dynamic Light Scattering (DLS) indicated the formation of surfactant-stabilized PDMS-PEG nanoparticles of less than 170 nm, but in-house SAXS measurements revealed only a single peak due to dilution and instrumental limitations, which is not enough to resolve the internal structure of the nanoparticles and confirm whether hexosomes have actually been formed. Synchrotron SAXS (BL11-NCD-SWEET) at ALBA is therefore critical to fully resolve higher-order reflections, confirm the presence of hexagonal or other liquid crystalline phases in dilute dispersions, and extract precise structural parameters. Measurements on samples prepared from PDMS-PEG with different PEG chain lengths, at various concentrations and temperatures, are planned. The results will provide new insights into the phase behavior of PDMS-PEG copolymers in physiological conditions and advance their potential use in nanocarrier-based drug delivery.