A homogeneous distribution of nanoparticles can be used to enhance mechanical strength without decreasing flexibility (Ribeiro et al. The particle distribution is commonly tuned in order to change key material properties (Meth et al. The resulting properties depend on the composition, shape and size of the nanofillers, their volume fraction and their spatial distribution inside the matrix (Liu and Webster 2010 Nan et al. Nanocomposites contain nanoparticles in polymer or other matrices (Hanemann and Szabó 2010), where they tune mechanical, dielectric or optical properties. Gravity also changes the distribution of particles in composites that are prepared from colloidal precursors, thus affecting bulk properties. Simulated microgravity conditions were found to enhance nutrient supply and oxygen diffusion, resulting in reduced necrosis centers during the assembly of tissue aggregates (Unsworth and Lelkes 1998 Freed and Vunjak-Novakovic 1997 Barzegari and Saei 2012). In biology, microgravity offers potentials for tissue engineering by enabling the aggregation of cells and therefore the formation of larger cell constructs. 1997) and the formation of ionic crystals from solution, for example calcium phosphate (Madsen et al. 1999 McPherson and DeLucas 2015), viruses (Lorber 2008), semiconductors (Ahari et al. The gravitational level can affect the crystallization of macromolecules (McPherson 1997 Lorber 2002), proteins (DeLucas et al. 2011), and the resulting mechanical stresses (Cheng et al. Gravitational acceleration affects important colloids by changing sedimentation (DeLucas et al. The particle dynamics inferred from DLS on ground and in microgravity were in good agreement, demonstrating the possibility to perform reliable DLS measurements in a drop tower. The particles did not change their diameter in the observed temperature range. We observed nanoparticles with average gold core diameters of 7.8 nm and non-polar oleylamine shells that were dispersed in tetradecane and had an average hydrodynamic diameter of 21 nm.
#Dynamic light scattering nanoparticle series#
Particle dynamics were analyzed at constant temperature and after a rapid temperature drop using a series of DLS measurements with 1 s integration time. Light scattering experiments were performed in the drop tower at ZARM (Bremen, Germany) during a microgravity interval of 9.1 s and compared to measurements on ground. A DLS instrument was adapted to withstand the accelerations in a drop tower, and a liquid handling set-up was connected in order to stabilize the liquid temperature and enable rapid cooling or heating.
![dynamic light scattering nanoparticle dynamic light scattering nanoparticle](https://img.medicalexpo.com/images_me/photo-g/94317-10090438.jpg)
We used dynamic light scattering (DLS) to quantify the mobility of nanoparticles on ground and in microgravity. Gravity affects colloidal dispersions via sedimentation and convection.