The role of the external and internal shock-absorption effect in the aerosol codeposition of titanium dioxide and polystyrene particles

Aerosol deposition (AD) is a promising spray-coating process for producing dense ceramic coatings at room temperature on a wide variety of substrates. However, extensive lattice defects and high compressive residual stresses arising from the intense particle impact limit its applicability. Co-deposition of polymers and ceramics has emerged as a strategy to mitigate these issues by dissipating part of the ceramic particle impact energy through deformation of the polymer phase. A similar effect occurs when pure ceramic powders are deposited on soft polymer substrates. These internal and external shock-absorption effects modify the deposition mechanism and can increase crystallite size, reduce microstrain, and lower residual stresses. In this work, pure titanium dioxide (TiO2) powders and TiO2/Polystyrene composite powders were deposited on soft polymer substrates and hard borosilicate glass. High-resolution synchrotron X-ray diffraction and FIB-SEM cross-sections reveal how both shock-absorption effects influence microstructure and deposition behavior, demonstrating the beneficial role of polymer incorporation in reducing defects and residual stresses.