@article{farrell_jacob_truong_elbourne_kong_hsiao_dickey_tabor_2023, title={Compositional Design of Surface Oxides in Gallium-Indium Alloys}, volume={1}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.2c02696}, DOI={10.1021/acs.chemmater.2c02696}, abstractNote={Room-temperature liquid metal alloys encompass a highly versatile family of materials possessing a unique set of chemical, electronic, biological, and mechanical properties. The surface oxide of liquid metals has a direct influence on these properties and is often composed of one of the major alloy components (i.e., gallium or indium). However, this is not a foregone conclusion, as the identity of the surface oxide can be altered by the addition of minority elements into the liquid metal. Through judicious choice of a minority alloying metal, the composition of the oxide and therefore the resulting molten alloy’s properties are significantly modified. We demonstrate this by adding a small amount (∼5%) of several thermodynamically favorable alloying elements (X = Zn, Mg, Al) to eutectic gallium indium (EGaIn), resulting in a new class of alloys with designed surface oxide compositions that we term XGaIn. Using both STEM-EDS and XPS, XGaIn alloys are shown to form oxide layers enriched in the lowest-redox element as expected based on the thermodynamics of the alloy system. This approach is shown to be generalizable across both Ga and non-Ga-based liquid metal alloy compositions. XGaIn alloys with added Zn and Mg are shown to have strong antimicrobial activity, which has exciting implications for the development of flexible electronic medical devices and sensors.}, journal={CHEMISTRY OF MATERIALS}, author={Farrell, Zachary J. and Jacob, Alan R. and Truong, Vi Khanh and Elbourne, Aaron and Kong, Wilson and Hsiao, Lilian and Dickey, Michael D. and Tabor, Christopher}, year={2023}, month={Jan} }
 @article{pradeep_nabizadeh_jacob_jamali_hsiao_2021, title={Jamming Distance Dictates Colloidal Shear Thickening}, volume={127}, ISSN={["1079-7114"]}, url={https://doi.org/10.1103/PhysRevLett.127.158002}, DOI={10.1103/PhysRevLett.127.158002}, abstractNote={We report experimental and computational observations of dynamic contact networks for colloidal suspensions undergoing shear thickening. The dense suspensions are comprised of sterically stabilized poly(methyl methacrylate) colloids that are spherically symmetric and have varied surface roughness. Confocal rheometry and dissipative particle dynamics simulations show that the shear thickening strength β scales exponentially with the scaled deficit contact number and the scaled jamming distance. Rough colloids, which experience additional rotational constraints, require an average of 1.5-2 fewer particle contacts as compared to smooth colloids, in order to generate the same β. This is because the surface roughness enhances geometric friction in such a way that the rough colloids do not experience a large change in the free volume near the jamming point. The available free volume for colloids of different roughness is related to the deficiency from the maximum number of nearest neighbors at jamming under shear. Our results further suggest that the force per contact is different for particles with different morphologies.}, number={15}, journal={PHYSICAL REVIEW LETTERS}, author={Pradeep, Shravan and Nabizadeh, Mohammad and Jacob, Alan R. and Jamali, Safa and Hsiao, Lilian C.}, year={2021}, month={Oct} }
 @article{williams_roh_jacob_stoyanov_hsiao_velev_2021, title={Printable homocomposite hydrogels with synergistically reinforced molecular-colloidal networks}, volume={12}, ISSN={2041-1723}, url={http://dx.doi.org/10.1038/s41467-021-23098-9}, DOI={10.1038/s41467-021-23098-9}, abstractNote={Abstract}, number={1}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Williams, Austin H. and Roh, Sangchul and Jacob, Alan R. and Stoyanov, Simeon D. and Hsiao, Lilian and Velev, Orlin D.}, year={2021}, month={May}, pages={2834} }
 @article{jacob_poulos_semenov_vermant_petekidis_2019, title={Flow dynamics of concentrated starlike micelles: A superposition rheometry investigation into relaxation mechanisms}, volume={63}, ISSN={["1520-8516"]}, DOI={10.1122/1.5086022}, abstractNote={The steady state flow of a concentrated dispersion of starlike micelles above the colloidal glass transition concentration is interrogated by superimposing a small amplitude straining motion orthogonal to the main flow direction. Strain amplitude sweeps reveal that the linear response region of the orthogonal perturbation increases with increasing flow rate, consistent with a fluidization of the materials. Orthogonal dynamic frequency sweeps (ODFSs) are obtained for a wide range of shear rates probing the full flow curve. The shear-induced fluidization of the initially glassy suspension is more clearly evidenced by the appearance of a crossover frequency ωc in ODFS, which steadily increases, reflecting a faster structural relaxation under shear. The dependence of ωc on the shear rate is sublinear and follows a power law with an exponent of 0.8. We show that the shape of the orthogonal viscoelastic spectrum changes at a critical shear rate γ˙cr, indicative of a structural relaxation modulus that changes from exponential at lower shear rates to multistep with alternating exponential and power law response at higher shear rates. We finally provide a theoretical framework which explains the observed sublinear power law dependence of the crossover frequency and relates it with the shear rate dependence of the viscosity measured by the flow curve.}, number={4}, journal={JOURNAL OF RHEOLOGY}, author={Jacob, Alan R. and Poulos, Andreas S. and Semenov, Alexander N. and Vermant, Jan and Petekidis, George}, year={2019}, month={Jul}, pages={641–653} }
 @article{sentjabrskaja_hendricks_jacob_petekidis_egelhaaf_laurati_2018, title={Binary colloidal glasses under transient stress- and strain-controlled shear}, volume={62}, ISSN={["0148-6055"]}, DOI={10.1122/1.5009193}, abstractNote={We investigate the yielding and transition to flow of different colloidal glasses. Using a single model system, a binary mixture of colloidal hard spheres with different compositions and size ratios, we study single, double and asymmetric glasses, which differ in the degree of mobility of the small particles and the caging mechanisms of the large spheres. The rheological response following either a step to a constant shear rate or to a constant stress (creep) is measured and the two responses are quantitatively compared. Although the same steady state of flow is observed at long times, the transient responses in strain- and stress-controlled experiments differ significantly. To achieve yielding and a steady state of flow, less time and less energy input is required if a constant strain rate is applied. Moreover, larger strain rates or stresses result in faster yielding and flow, but require more total energy input. If a constant strain rate is applied, yielding and the transition to flow depend on the pro...}, number={1}, journal={JOURNAL OF RHEOLOGY}, author={Sentjabrskaja, Tatjana and Hendricks, Jan and Jacob, Alan R. and Petekidis, George and Egelhaaf, Stefan U. and Laurati, Marco}, year={2018}, month={Jan}, pages={149–159} }
 @article{moghimi_jacob_petekidis_2017, title={Residual stresses in colloidal gels}, volume={13}, ISSN={["1744-6848"]}, DOI={10.1039/c7sm01655g}, abstractNote={A combination of experiments and Brownian Dynamics (BD) simulations is utilized to examine internal stresses in colloidal gels brought to rest from steady shear at different shear rates.}, number={43}, journal={SOFT MATTER}, author={Moghimi, Esmaeel and Jacob, Alan R. and Petekidis, George}, year={2017}, month={Nov}, pages={7824–7833} }