Hybrid assembly of layered double hydroxide nanocrystals with inorganic, polymeric and biomaterials from micro- to nanometer scales

Monolayer assemblies of zeolite microcrystals, polymer nanobeads and caged proteins were successfully applied to a highly ordered MgAl-LDH monolayer by using the electrostatic attractions between the negatively charged particles and positively charged MgAl-LDH without chemical modifications. Ultrasonication leads to the monolayer assembly of ZSM-5 microcrystals with a maximum preferred contact over the MgAl-LDH monolayer, where the ZSM-5 microcrystals are oriented in the (0k0) crystallographic direction. PMMA and ferritin were also adsorbed on the monolayer LDH nanocrystal surface through self-assembly in solution. Homogeneous PMMA colloids-LDH composite layers on Si were successfully prepared, thanks to the improved interfacial compatibility between the immobilized LDH and polymer surface charges. Thermal treatment at 150°C resulted in the formation of continuous polymer coatings over the LDH/Si monolayer. The mixing of colloidal solutions of LDH and PMMA led to the formation of bulk-type polymer-LDH composites after the melting of the polymer phase, where the polymer was homogeneously coated over the LDH crystals without the phase segregation of the LDH nanocrystals. The charged hydroxide layers of the LDH nanocrystals provided the multifunctional interface characteristics required to assemble the functional particles, resulting in the binary hybrid structures of inorganic-inorganic, polymer-inorganic or bio-inorganic composites.