Controllable Fabrication of Highly Uniform Sub-10 nm Nanoparticles from Spontaneous Confined Nanoemulsification.

Sub-10 nm nanoparticles are known to exhibit extraordinary size-dependent properties for wide applications. Many approaches have been developed for synthesizing sub-10 nm inorganic nanoparticles, but the fabrication of sub-10 nm polymeric nanoparticles is still challenging. Here, a scalable, spontaneous confined nanoemulsification strategy that produces uniform sub-10 nm nanodroplets for template synthesis of sub-10 nm polymeric nanoparticles is proposed. This strategy introduces a high-concentration interfacial reaction to create overpopulated surfactants that are insoluble at the droplet surface. These overpopulated surfactants act as barriers, resulting in highly accumulated surfactants inside the droplet via a confined reaction. These surfactants exhibit significantly changed packing geometry, solubility, and interfacial activity to enhance the molecular-level impact on interfacial instability for creating sub-10 nm nanoemulsions via self-burst nanoemulsification. Using the nanodroplets as templates, the fabrication of uniform sub-10 nm polymeric nanoparticles, as small as 3.5 nm, made from biocompatible polymers and capable of efficient drug encapsulation is demonstrated. This work opens up brand-new opportunities to easily create sub-10 nm nanoemulsions and advanced ultrasmall functional nanoparticles.

Designable Micro-/Nano-Structured Smart Polymeric Materials.

Smart polymeric materials with dynamically tunable physico-chemical characteristics in response to changes of environmental stimuli, have received considerable attention in myriad fields. The diverse combination of their micro-/nano-structural and molecular designs creates promising and exciting opportunities for exploiting advanced smart polymeric materials. Engineering micro-/nano-structures into smart polymeric materials with elaborate molecular design enables intricate coordination between their structures and molecular-level response to cooperatively realize smart functions for practical applications. In this review, recent progresses of smart polymeric materials that combine micro-/nano-structures and molecular design to achieve designed advanced functions are highlighted. Smart hydrogels, gating membranes, gratings, milli-particles, micro-particles and microvalves are employed as typical examples to introduce their design and fabrication strategies. Meanwhile, the key roles of interplay between their micro-/nano-structures and responsive properties to realize the desired functions for their applications are emphasized. Finally, perspectives on the current challenges and opportunities of micro-/nano-structured smart polymeric materials for their future development are presented.