4 research outputs found
Direct Access to Hierarchically Porous Inorganic Oxide Materials with Three-Dimensionally Interconnected Networks
Hierarchically porous
oxide materials have immense potential for
applications in catalysis, separation, and energy devices, but the
synthesis of these materials is hampered by the need to use multiple
templates and the associated complicated steps and uncontrollable
mixing behavior. Here we report a simple one-pot strategy for the
synthesis of inorganic oxide materials with multiscale porosity. The
inorganic precursor and block copolymer are coassembled into an ordered
mesostructure (microphase separation), while the in situ-polymerized
organic precursor forms organic-rich macrodomains (macrophase separation)
around which the mesostructure grows. Calcination generates hierarchical
meso/macroporous SiO<sub>2</sub> and TiO<sub>2</sub> with three-dimensionally
interconnected pore networks. The continuous 3D macrostructures were
clearly visualized by nanoscale X-ray computed tomography. The resulting
TiO<sub>2</sub> was used as the anode in a lithium ion battery and
showed excellent rate capability compared with mesoporous TiO<sub>2</sub>. This work is of particular importance because it (i) expands
the base of BCP self-assembly from mesostructures to complex porous
structures, (ii) shows that the interplay of micro- and macrophase
separation can be fully exploited for the design of hierarchically
porous inorganic materials, and therefore (iii) provides strategies
for researchers in materials science and polymer science
Grafting of Polyimide onto Chemically-Functionalized Graphene Nanosheets for Mechanically-Strong Barrier Membranes
A series of polyimide (PI) nanocomposite
films with different loadings
of aminophenyl functionalized graphene nanosheets (AP-rGO) was fabricated
by in situ polymerization. AP-rGO, a multifunctional carbon nanofiller
that can induce covalent bonding between graphene nanosheets and the
PI matrix, was obtained through the combination of chemical reduction
and surface modification. In addition, phenyl functionalized graphene
nanosheets (P-rGO) were prepared by phenylhydrazine for reference
nanocomposite films. Because of homogeneous dispersion of AP-rGO and
the strong interfacial interaction between AP-rGO and the PI matrix,
the resulting nanocomposite films that contained AP-rGO exhibited
reinforcement effects of mechanical properties and oxygen barrier
properties that were even better than those of pure PI and the reference
nanocomposite films. In comparison to the tensile strength and tensile
modules of pure PI, the composite films that contained AP-rGO with
3 wt % loading were increased by about 106% (262 MPa) and 52% (9.4
GPa), respectively. Furthermore, the oxygen permeabilities of the
composites with 5 wt % filler content were significantly decreased,
i.e., they were more than 99% less than the oxygen permeability of
pure PI
Additional file 1: Table S1. of Prognostic impact of a new score using neutrophil-to-lymphocyte ratios in the serum and malignant pleural effusion in lung cancer patients
Multivariate analyses of the factors that are predictive of overall survival in all patients apart from the new score, which use the neutrophil-to-lymphocyte ratios in the serum and malignant pleural effusion. (DOCX 16.8Â kb
Biofunctionalized Ceramic with Self-Assembled Networks of Nanochannels
Nature designs circulatory systems with hierarchically organized networks of gradually tapered channels ranging from micrometer to nanometer in diameter. In most hard tissues in biological systems, fluid, gases, nutrients and wastes are constantly exchanged through such networks. Here, we developed a biologically inspired, hierarchically organized structure in ceramic to achieve effective permeation with minimum void region, using fabrication methods that create a long-range, highly interconnected nanochannel system in a ceramic biomaterial. This design of a synthetic model-material was implemented through a novel pressurized sintering process formulated to induce a gradual tapering in channel diameter based on pressure-dependent polymer agglomeration. The resulting system allows long-range, efficient transport of fluid and nutrients into sites and interfaces that conventional fluid conduction cannot reach without external force. We demonstrate the ability of mammalian bone-forming cells placed at the distal transport termination of the nanochannel system to proliferate in a manner dependent solely upon the supply of media by the self-powering nanochannels. This approach mimics the significant contribution that nanochannel transport plays in maintaining living hard tissues by providing nutrient supply that facilitates cell growth and differentiation, and thereby makes the ceramic composite “alive”