Because of some defects such as holes and cracks, the corrosion resistance of micro-arc oxidation coating needs to be improved by surface modification. In this paper, LDH/MAO film with a micro-/nano-structure is constructed on the surface of AZ31 magnesium alloy by controlling the composition and concentration of the hydrothermal solution. The superhydrophobic surface is successfully constructed by coating an OTES modifier on the surface of LDH/MAO film by the spin-coating method. The surface morphologies, contact angles, and corrosion resistance of composite coatings are tested. The results show that the OTES-LDH/MAO composite coatings of magnesium alloy can seal the defects in the MAO film well to achieve a superhydrophobic effect and better corrosion resistance. Compared with a MgO ceramic film, the water contact angle of OTES-LDH/MAO composite coatings is increased from 38° to 155°; the corrosion potential increases by 0.7 V, the corrosion current density and polarization resistance decreases and increases by four orders of magnitude, respectively; and the corrosion resistance becomes much higher than that of MAO film.

A La_0.67Sr_0.33MnO₃ (LSMO) ferromagnetic layer and a Nd³⁺/Hf⁴⁺ co-substituted Bi₄Ti₃O₁₂ (Bi_3.15Nd_0.85Ti_3-xHf_xO₁₂ (BNTH_x, x = 0, 0.025, 0.05, 0.1 and 0.15)) ferroelectric layer were successively deposited onto the (00 l)-oriented LaNiO₃ (LNO) layer buffered (001) Si substrate via all chemical solution deposition (CSD) method. As a result, the BNTH_x/LSMO ferromagnetic-ferroelectric composite films integrated on Si substrate exhibit high c-axis orientation. The Nd³⁺/Hf⁴⁺ co-substituted BNTH_x films have the lower leakage current and the better ferroelectric properties than the mono-substituted Bi₄Ti₃O₁₂ (Bi_3.15Nd_0.85Ti₃O₁₂ and Bi₄Ti_2.95Hf_0.05O₁₂) films. In particular, the BNTH_0.05/LSMO/LNO film has the lowest leakage current density of 2.5 × 10⁻⁷ A/cm² at 200 kV/cm, and the highest remnant polarization (Pr) of 27.3 μC/cm². The BNTH_0.05/LSMO/LNO composite film also exhibits the soft ferromagnetism characteristics with a high saturated magnetization of 258 emu/cm³ at 300 K, and the excellent magnetoelectric (ME) effect. The variations of ME voltage coefficient α_E values with DC bias magnetic field H_bias shows that the BNTH_0.05/LSMO/LNO film has the high α_E value at near zero H_bias. Moreover, at H_bias = 0 Oe, the α_E value gradually increases from zero with the increasing of the AC magnetic field frequency, and eventually reaches about 18.9 V/cm·Oe at 100 kHz, suggesting the existence of self-biased ME effect.

A π-conjugated thiophene-containing oligomer with a D-A-D-A-D (D: donor, A: acceptor) architecture, namely, 2,6-bis{[4-(7-n-hexylthiophen-2-yl)thiophen-2-yl]-(dibenzothiophene-5,5-dioxide-3,3΄-diyl)}-bis((2-ethyl-hexyl)oxy)benzo[1,2-b:4,5-b’]dithiophen (BDT(DBTOTTH)₂), was synthesized by Stille coupling reactions. There are obvious shifts in the Ultraviolet-visible (UV-vis) and photoluminescence (PL) spectra of the thin film relative to its solution, indicating the existence of the π-π stacking in the solid state of the oligomer BDT(DBTOTTH)₂. The optical band gap of the oligomer determined from its absorption onset in UV-Vis spectra is 2.25 eV. It agrees with the value of 2.29 eV determined from the cyclic voltammetry (CV) measurement. Its highest occupied and lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, which were calculated from its onset of oxidation and reduction waves in CV curve, are −5.51 and −3.22 eV, respectively. The oligomer is a P-type semiconductor material with a good thermal stability and solubility, which can be used to fabricate organic field effect transistors (OFETs) by the spin coating technique. The OFET with n-octadecanylltrichlorosilane (OTS)-modified SiO₂ dielectric layer exhibited a mobility of 1.6 × 10⁻³ cm²/Vs.