Project Details
Projekt
Microgels that Swim on the Beat of Light
Applicants
Dr. Ahmed Mourran; Professor Dr. Martin Möller
Subject Area
Preparatory and Physical Chemistry of Polymers
Polymer Materials
Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
Polymer Materials
Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
Term
from 2014 to 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 255087333
We focus on thin poly(N-isopropylacrylamide) (PNIPAm) microgel bodies which undergo bending and torsional motions upon swelling and deswelling. Very fast temperature jumps localized to the volume of the thin microgel body are achieved by photothermal heating with gold nanorods that have been embedded within the temperature responsive PNIPAm microgel. Irradiation by near IR-light and conversion to heat is engineered to enable jumps in temperature by up to more than 20°C within milliseconds and less. Because the heating is restricted to the inner volume of small microgel objects, they also cooled down quickly by fast heat transfer to the surrounding bath when the heating was ceased. Because swelling and shrinkage is diffusion controlled and cannot follow fast temperature changes in time, the volume change is effectuated out of equilibrium. We plan to develop further the control, understanding, and directing of the motion of a deforming bilayer ribbon by systematic and rational variation of its geometrical design and of the off-equilibrium actuation. So far we have achieved directed motility by empirical exploration of the modes of motion and developed a first understanding by the analysis of the involved modes of motion. In the second phase of the project we will focus on the (i) elimination of wall effects, (ii) precise measurements of the temperature development within the gel object (iii) breaking the symmetry of the ribbon by distinct ends, variation in the density, the crosslinking or of the geometry along the ribbon, (iv) exploring resonance effects and the possibility for even faster actuation, (v) effects of an increase in the viscosity of the medium, (vi) end-coupling of different helices to micro objects like polymer vesicles (polymersomes) or small surfactant stabilized oil droplets, (vii) motion trajectories will be carefully documented and experimentally adjusted for evaluation by other groups within the SPP.
DFG Programme
Priority Programmes
