Microfluidic Synthesis of Liquid Crystalline Elastomer Particle Transport Systems which Can Be Remote‐Controlled Magnetically

Abstract

Here, the microfluidic synthesis of liquid crystalline elastomer (LCE) particles, which can be remote-controlled magnetically and used as transport systems, is presented for the first time. Ferri-magnetic, rod-shaped Fe 3 O 4 nanoparticles are functionalized with poly(methyl methacrylate) to make them compatible with organic LCE precursor compounds. Their influence on the LCE precursor alignment is studied and thermoresponsive as well as photoresponsive LCE microparticles containing 0-6 wt% Fe 3 O 4 are synthesized with a microfluidic device. Thermal and photochemical actuations of these particles are investigated. Their magnetic addressability is studied with a recently developed magnetic setup, by which the particles can be guided on liquid surfaces in the centimeter range-but with a precision in the submillimeter range. This allows the performance of reversible light-or heat-controlled actuations at desired positions. The potential of synthesized LCE particles as transport systems is demonstrated by the transport of plastic, textiles or copper, which can be pushed just due to magnetic forces or transported in general by taking advantage of the phase dependent "stickiness" of LCEs. These studies open doors to novel applications of LCEs as microrobots using magnetism as a control.

Efficient Chain Formation of Magnetic Particles in Elastomers with Limited Space

“…Magnetic elastomers are a type of stimuli-responsive soft material [1][2][3][4][5] and its physical properties alter in response to magnetic fields. The magnetic response for a magnetic elastomer is in general drastic; therefore, the material attracts considerable attention as actuators in the next generation of materials [6][7][8]. Magnetic elastomers consist of polymeric matrices, such as polyurethane, and magnetic particles with nano or micron sizes in diameter.…”

Controlled Movement of Complex Double Emulsions via Interfacially Confined Magnetic Nanoparticles

“…Specifically, this functionalization enables translational movements toward the magnet. 31 Alternatively, MNPs dispersed in cholesteric single emulsions showed a programmable assembly in the internal disclinations of the cholesteric phase. 32 Herein, we make use of Janus emulsions comprising two immiscible phases, nematic LC (4-cyano-4′-pentylbiphenyl, 5CB) and FC oil (ethyl perfluorobutyl ether, HFE-7200), to organize MNPs.…”

From LC‐polymers to Nanomedicines: Different Aspects of Polymer Science from a Materials Viewpoint

“…Microfluidics, on the other side, allows the preparation of actuating particles of various shape (spheres, fibers, tubes, and hollow spheres), which can be transported over the cm range with magnetic fields and which change their shape on temperature variation or by irrigation with light …”

“…[48] Microfluidics, on the other side, allows the preparation of actuating particles of various shape (spheres, fibers, tubes, and hollow spheres), [49][50][51] which can be transported over the cm range with magnetic fields and which change their shape on temperature variation or by irrigation with light. [52,53] In addition-in cooperation with engineers-mechanical micromachines with LCEs as the (temperature sensitive, but) electrically addressable actuators could be build (see Figure 1c) and used as active element in optical applications, [54,55] for example, to build an artificial, camera-like eye.…”