Poly(N-isopropylacrylamide) (PNIPAM)-based thermosensitive hydrogels demonstrate great potential in biomedical applications. However, they have inherent drawbacks such as low mechanical strength, limited drug loading capacity and low biodegradability. Formulating PNIPAM with other functional components to form composited hydrogels is an effective strategy to make up for these deficiencies, which can greatly benefit their practical applications. This review seeks to provide a comprehensive observation about the PNIPAM-based composite hydrogels for biomedical applications so as to guide related research. It covers the general principles from the materials choice to the hybridization strategies as well as the performance improvement by focusing on several application areas including drug delivery, tissue engineering and wound dressing. The most effective strategies include incorporation of functional inorganic nanoparticles or self-assembled structures to give composite hydrogels and linking PNIPAM with other polymer blocks of unique properties to produce copolymeric hydrogels, which can improve the properties of the hydrogels by enhancing the mechanical strength, giving higher biocompatibility and biodegradability, introducing multi-stimuli responsibility, enabling higher drug loading capacity as well as controlled release. These aspects will be of great help for promoting the development of PNIPAM-based composite materials for biomedical applications.

The extremely low room-temperature ionic conductivity of solid-state polymer electrolytes (SPEs) ranging from 10-7 to 10-5 S cm-1 seriously restricts their practical application in solid-state lithium metal batteries (LMBs). Herein,...

Ultrathin two-dimensional metal−organic frameworks (2D MOFs) have the potential to improve the performance of Li−O 2 batteries with high O 2 accessibility, open catalytic active sites, and large surface areas. To obtain highly efficient cathode catalysts for aprotic Li−O 2 batteries, a facile ultrasonicated method has been developed to synthesize three kinds of 2D MOFs (2D Co-MOF, Ni-MOF, and Mn-MOF). Contributing from the inherent open active sites of the Mn−O framework, the discharge specific capacity of 9464 mAh g −1 is achieved with the 2D Mn-MOF cathode, higher than those of the 2D Co-MOF and Ni-MOF cathodes.During the cycling test, the 2D Mn-MOF cathode stably operates more than 200 cycles at 100 mA g −1 with a curtailed discharge capacity of 1000 mAh g −1 , quite longer than those of others. According to further electrochemical analysis, we observe that the 2D Mn-MOF outperforms 2D Ni-MOF and Co-MOF due to a superior oxygen reduction reactions and oxygen evolution reactions activity, in particular, the efficient oxidation of both LiOH and Li 2 O 2 . The present study provides new insights that the 2D MOF nanosheets can be well applied as the Li−O 2 cells with high energy density and long cycling life.

Transparent/translucent glass ceramics (GCs) have broad applications in biomedicine, armor, energy, and constructions. However, GCs with improved optical properties typically suffer from impaired mechanical properties, compared to traditional sintered full-ceramics. We present a method of obtaining high-strength, translucent GCs by preparing ZrO2–SiO2 nanocrystalline glass ceramics (NCGCs) with a microstructure of monocrystalline ZrO2 nanoparticles (NPs), embedded in an amorphous SiO2 matrix. The ZrO2–SiO2 NCGC with a composition of 65%ZrO/35%SiO2 (molar ratio, 65Zr) achieved an average flexural strength of 1 GPa. This is one of the highest flexural strength values ever reported for GCs. ZrO2 NPs bond strongly with SiO2 matrix due to the formation of a thin (2–3 nm) amorphous Zr/Si interfacial layer between the ZrO2 NPs and SiO2 matrix. The diffusion of Si atoms into the ZrO2 NPs forms a ZrOSi superlattice. Electron tomography results show that some of the ZrO2 NPs are connected in one direction, forming in situ ZrO2 nanofibers (with length of ∼500 nm), and that the ZrO2 nanofibers are stacked in an ordered way in all three dimensions. The nanoarchitecture of the ZrO2 nanofibers mimics the architecture of mineralized collagen fibril in cortical bone. Strong interface bonding enables efficient load transfer from the SiO2 matrix to the 3D nanoarchitecture built by ZrO2 nanofibers and NPs, and the 3D nanoarchitecture carries the majority of the external load. These two factors synergistically contribute to the high strength of the 65Zr NCGC. This study deepens our fundamental understanding of the microstructure-mechanical strength relationship, which could guide the design and manufacture of other high-strength, translucent GCs.

Solid polymer electrolyte for solid state lithium metal batteries faces the challenges of low ionic conductivity, poor mechanical property and large thickness. Herein, a thin and high strength composite polymer...