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A simple synthesis method combining a sol‐gel route followed by a reduction step is developed for the fabrication of magnetophotonic crystal (MPC) materials from Morpho butterfly wings. The sol‐gel route leads to hematite with a photonic crystal structure (PC‐α‐Fe2O3) being faithfully replicated from a biotemplate, and the desired magnetophotonic crystal Fe3O4 (MPC‐Fe3O4) is obtained by the reduction of the PC‐α‐Fe2O3 under a H2/Ar atmosphere. The structural replication fidelity of the process is demonstrated on both the macro‐ and microscale, and even down to the nanoscale, as evidenced by scanning electron microscopy, X‐ray diffraction, reflectance measurements, and transmission electron microscopy. It is found that the chemical transformation of PC‐α‐Fe2O3 to MPC‐Fe3O4 changes only the dielectric constant and does not induce structural defects that could affect the photonic‐crystal properties of the composite. The photonic band gap of MPC‐Fe3O4 can be red‐shifted with an increase of the external magnetic field strength, which is further supported by theoretical calculations. The reported biomimetic technique provides an effective approach to produce magnetophotonic crystals from nature with 3D networks, which may open up an avenue for the creation of new magneto‐optical devices and theoretical research in this field.

CO2 gas sensing is of great importance because of the impact of CO2 on global climate change. Here, utilizing an inverse opal hydrogel, we describe a CO2 gas sensing method that allows highly sensitive and selective detection over a wide concentration range. The CO2 sensor is specific, quantitative, interference tolerant and without the need for special instruments.

Inverse‐opal strong polyelectrolyte sensors, achieved by using a colloidal crystal templating method, respond sensitively and universally to various anions, cations, and zwitterions with brilliant structural colors that can even be observed by the naked eye. They are very attractive for a range of applications, such as ion detection, separation, ionic conduction, and catalysts.

Among many thermo-photochromic materials, the color-changing behavior caused by temperature and light is usually lack of a full color response. And the study on visible light-stimuli chromic response is rarely reported. Here, we proposed a strategy to design a thermo-photochromic chameleon biomimetic material consisting of photonic poly(N-isopropylacrylamide-co-methacrylic acid) copolymer and plasmonic nanoparticles which has a vivid color change triggered by temperature and light like chameleons. We make use of the plasmonic nanoparticles like gold nanoparticles and silver nanoparticles to increase the sensitivity of the responsive behavior and control the lower critical solution temperature of the thermosensitive films by tuning the polymer chain conformation transition. Finally, it is possible that this film would have colorimetric responses to the entire VIS spectrum by the addition of different plasmonic nanoparticles to tune the plasmonic excitation wavelength. As a result, this method provides a potential use in new biosensors, military and many other aspects.