Diffusion is one of the key nature processes which plays an important role in respiration, digestion, and nutrient transport in cells. In this regard, the present article aims to review various diffusion approaches used to fabricate different functional materials based on hydrogels, unique examples of materials that control diffusion. They have found applications in fields such as drug encapsulation and delivery, nutrient delivery in agriculture, developing materials for regenerative medicine, and creating stimuli-responsive materials in soft robotics and microrobotics. In addition, mechanisms of release and drug diffusion kinetics as key tools for material design are discussed.

Ultrasound processes are particularly interesting for a great variety of applications like formation of developed surfaces, finishing, catalyst formation, polymerization and surface polymer attachment, etc. Here, we report on the ultrasound-driven formation of metal surface nanofoams in aqueous media. Systematic investigation of ultrasound effects on various types of aluminium, iron and magnesium alloys shows that the character of the metal determines the roughness of the metal surface. A trick with attachment of layered double hydroxide laurate to a nanostructured aluminium-based foam surface results in the formation of a corrosion-resistant superhydrophobic surface.