A water suspension of nanocomposite microcapsules with embedded ZnO nanoparticles in the capsule shell is reported. The microcapsule morphology is characterized by confocal microscopy, TEM, SEM, and AFM before and after ultrasound treatment. A remarkably high capsule sensitivity to ultrasound is evidenced, and it is observed to grow with increasing number of ZnO nanoparticle layers in the nanocomposite shell. This effect is correlated with the mechanical properties of microcapsules measured with AFM.

Controlled formation of a variety of 3D structures was observed at high polymer weight fractions in water from a single diblock, consisting of poly(N-isopropylacrylamide), PNIPAM, and polystyrene, PSTY segments. The structures form through a mechanical process driven by swelling of hydrophilic polymer segments upon a change in temperature.

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Thermoresponsive polymer-coated surfaces based on poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methacrylate) [P(MEO(2)MA-co-OEGMA)] allow switching between cell attachment and detachment. Here, we investigate the temperature-dependent surface interactions between the polymer coating and a colloidal probe in an aqueous medium by means of atomic force microscopy (AFM) force-distance measurements. The analysis of the adhesion forces from AFM retraction curves identifies two kinds of regimes for the copolymer at temperatures below and above the lower critical solution temperature (LCST). Whereas at 25 degrees C the surface interactions with the polymer in the swollen state are dominated by repulsive forces, at 37 degrees C the surface interactions switch to attractive forces and a stronger adhesion is detected by AFM. Running several heating/cooling cycles repeatedly shows that switching the surface properties provides reproducible adhesion force values. Time-dependent measurements give insight into the switching kinetics, demonstrating that the cell response is coupled to the polymer kinetics but probably limited by the cellular rearrangements.