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Abstract: Surface hydrophobization of cellulose nanomaterials has been used in the development of nanofiller reinforced polymer composites and formulations based on Pickering emulsions. Despite well known effect of hydrophobic domains on self assembly or association of water soluble polymer amphiphiles, very few studies have addressed the behavior of hydrophobized cellulose nanomaterials in aqueous media. In this study, we investigate the properties of hydrophobized cellulose nanocrystals (CNCs) and their self assembly and amphiphilic properties in suspensions and gels. CNCs of different hydrophobicity were synthesized from sulfated CNCs by coupling primary alkylamines of different alkyl chain lengths (6, 8 and 12 carbon atoms). The synthetic route permitted the retention of surface charge, ensuring good colloidal stability of hydrohobized CNCs in aqueous suspensions. We compare surface properties (surface charge, Zeta potential), hydrophobicity (water contact angle, microenvironment probing using pyrene fluorescence emission) and surface activity (tensiometry) of different hydrophobized CNCs and hydrophilic CNCs. Association of hydrophobized CNCs driven by hydrophobic effects is confirmed by X ray scattering (SAXS) and autofluorescent spectroscopy experiments. As a result of CNC association, CNCs suspensions/gels can be produced with a wide range of rheological properties depending on the hydrophobic/hydrophilic balance. In particular, sol gel transitions for hydrophobized CNCs occur at lower concentrations then hydrophilic CNCs and more robust gels are formed by hydrophobized CNCs. Our work illustrates that amphiphilic CNCs can complement associative polymers as modifiers of rheological properties of water based systems.

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Abstract: Understanding structure-property relationships is critical for the development of new drug delivery systems. This study investigates the properties of Pluronic smart hydrogel formulations for future use as injectable controlled drug carriers. The smart hydrogels promise to enhance patient compliance, decrease side effects and reduce dose and frequency. Pharmaceutically, these systems are attractive due to their unique sol-gel phase transition in the body, biocompatibility, safety and injectability as solutions before transforming into gel matrices at body temperature. We quantify the structural changes of F127 systems under controlled temperature after flow, as experienced during real bodily injection. Empirical formulae combining the coupled thermal and shear dependency are produced to aid future application of these systems. Induced structural transitions measured in-situ by small angle x-ray and neutron scattering reveal mixed oriented structures that can be exploited to tailor the drug release profile.

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Abstract: It is now well established that cell membranes are much more than a barrier that separate the cytoplasm from the outside world. Regarding membrane's lipids and their self-assembling, the system is highly complex, for example, the cell membrane needs to adopt different curvatures to be functional. This is possible thanks to the presence of non-lamellar-forming lipids, which tend to curve the membrane. Here, we present the effect of squalane, an apolar isoprenoid molecule, on an archaea-like lipid membrane. The presence of this molecule provokes negative membrane curvature and forces lipids to self-assemble under inverted cubic and inverted hexagonal phases. Such non-lamellar phases are highly stable under a broad range of external extreme conditions, e.g. temperatures and high hydrostatic pressures, confirming that such apolar lipids could be included in the architecture of membranes arising from cells living under extreme environments.

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Abstract: The single gyroid phase as well as the alternating double network gyroid, composed of two alternating single gyroid networks, hold a significant place in ordered nanoscale morphologies for their potential applications as photonic crystals, metamaterials and templates for porous ceramics and metals. Here we report the first alternating network cubic liquid crystals. They form through self‐assembly of X‐shaped polyphiles, where the glycerol‐capped terphenyl rods lie on the gyroid surface while the semiperfluorinated and aliphatic side‐chains fill their respective separate channel networks. This new self‐assembly mode can be considered as a two‐color symmetry‐broken double gyroid morphology, providing a tailored way to fabricate novel chiral structures with sub‐10 nm periodicities using achiral compounds.

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Abstract: Dispersions of non-lamellar lipid membrane assemblies are gaining increasing interest for drug delivery and protein therapeutic application. A key bottleneck has been the lack of rational design rules for these systems linking different lipid species and conditions to defined lattice parameters and structures. We have developed robust methods to form cubosomes (nanoparticles with a porous internal structure) with water channel diameters of up to 171 Å which are over 4 times larger than archetypal cubosome structures. The water channel diameter can be tuned via the incorporation of cholesterol and the charged lipids DOPA, DOPG or DOPS. We have found that large molecules can be incorporated into the porous cubosome structure and these molecules can interact with the internal cubosome membrane. This offers huge potential for accessible encapsulation and protection of biomolecules, and development of confined interfacial reaction environments.