Large shifts of the selective reflection band and colour changes are achieved in highly viscous mixtures of cholesteric polymers and low molar mass liquid crystals subject to mechanical deformation. The liquid crystal mixture was sandwiched between two silicone strips and stretched. The colour of the material changed instantaneously during stretching, and the time for the colour to be completely restored increased with the viscosity of the polymer mixture. A quantitative model considering the material as an incompressible viscoelastic fluid is proposed. The model accurately describes colour changes (shift of the selective reflection band) and its relaxation back to the original spectral location.

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The improved performance is demonstrated for mechanical sensors based on cholesteric paint covering elastic silicone substrate with imprinted grooves. Due to the presence of the grooves, the deformation of the substrate is translated to the deformation of the cholesteric paint differently along the grooves and perpendicular to them. The model is suggested to describe the anisotropy of deformations and color changes.

Large spectral shifts of the selective reflection band and color changes are achieved in highly viscous mixture of cholesteric polymers and low molar mass liquid crystals filled with nanoparticles and subject to mechanical deformations. The color of the material changes instantaneously during deformation; the time for the color to be completely restored increased with the viscosity of the polymer mixture. The viscosity increases with increasing concentration of polymer or nanoparticles. These properties of the material were explored in building a highly sensitive mechanical sensor.