Shunai Che

Nanosheet‐Constructed Porous TiO2–B for Advanced Lithium Ion Batteries

Hierarchical porous TiO(2)-B with thin nanosheets is successfully synthesized. TiO(2)-B polymorph ensures fast insertion of Li-ion due to its pseudocapacitive mechanism. The thin nanosheet walls with porous structure allow exposure to electrolytes for facile ionic transport and interfacial reaction. The joint advantages endow this material with high reversible capacity, excellent cycling performance, and superior rate capability.

Coordination Polymer Coated Mesoporous Silica Nanoparticles for pH‐Responsive Drug Release

Coordination polymer coated mesoporous silica nanoparticles for drug delivery are successfully synthesized. The system ensures that drugs are stored in the mesopores under a physiological environment. Upon H(+) stimulus in the endosomal and lysosomal compartments, the drugs are released into the intracellular organelles of cancer cells, effectively killing the cells.

Gold nanorod@chiral mesoporous silica core-shell nanoparticles with unique optical properties.

The design and fabrication of chiral nanostructures is a promising approach to realize enantiomeric recognition and separation. In our work, gold nanorod@chiral mesoporous silica core-shell nanoparticles (GNR@CMS NPs) have been successfully synthesized. This novel material exhibits strong and tunable circular dichroism signals in the visible and near-infrared regions due to the optical coupling between the CMS shells and the GNR cores. When chiral cysteine molecules are loaded in the porous shells, the corresponding surface enhanced Raman scattering spectroscopy demonstrates a distinct chiral recognition effect, which can be used to semiquantitatively measure the composition of chiral enantiomers. A detailed sensing mechanism has been disclosed by density functional theory calculations.

Synthesis of chiral TiO 2 nanofibre with electron transition-based optical activity

The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO2 fibres via transcription of the helical structure of amino acid-derived amphiphile fibres through coordination bonding interactions between the organics and the TiO2 source. Upon calcination, the as-prepared amorphous TiO2 double-helical fibres with a pitch length of ~100 nm were converted to double-helical crystalline fibres with stacks of anatase nanocrystals in an epitaxial helical relationship. Both the amorphous and anatase crystalline helical TiO2 fibres exhibited optical response to circularly polarized light at the absorption edge around ~350 nm. This was attributed to the semiconductor TiO2-based electronic transitions from the valence band to the conduction band under an asymmetric electric field.

π–π interaction of aromatic groups in amphiphilic molecules directing for single-crystalline mesostructured zeolite nanosheets

One of the challenges in material science has been to prepare macro- or mesoporous zeolite. Although examples of their synthesis exist, there is a need for a facile yet versatile approach to such hierarchical structures. Here we report a concept for designing a single quaternary ammonium head amphiphilic template with strong ordered self-assembling ability through π-π stacking in hydrophobic side, which stabilizes the mesostructure to form single-crystalline mesostructured zeolite nanosheets. The concept is demonstrated for the formation of a new type of MFI (zeolite framework code by International Zeolite Association) nanosheets joined with a 90° rotational boundary, which results in a mesoporous zeolite with highly specific surface area even after calcination. Low binding energies for this self-assembling system are supported by a theoretical analysis. A geometrical matching between the arrangement of aromatic groups and the zeolitic framework is speculated for the formation of single-crystalline MFI nanosheets.

Supramolecular chiral transcription and recognition by mesoporous silica prepared by chiral imprinting of a helical micelle.

Lets twist again: The chirality of a helical propeller-like micelle has been memorized by functional groups on the mesopore surface of chiral mesoporous silicas. Such imprinted supramolecular chirality can be transcripted to poly(propiolic acid) sodium salt and tetraphenylporphine tetrasulfonic acid (see picture), and recognized by B-DNA.

Synthesis of carboxylic group functionalized mesoporous silicas (CFMSs) with various structures

Carboxylic group functionalized mesoporous silicas (CFMSs) were successfully synthesized by using cationic surfactants as templates and carboxyethylsilanetriol sodium salt (CES) as a co-structure directing agent (CSDA). Well ordered two-dimensional (2D) p6mm, cubic Fmm, intergrowth of Fmm and P63/mmc, and cubic Fdm with uniform carboxyl group distributions have been synthesized with increasing charge density of carboxylate of CES on the surface of the mesopore, which will provide new families of mesoporous materials with different functionalities and structures.

Spontaneous formation and characterization of silica mesoporous crystal spheres with reverse multiply twinned polyhedral hollows.

A crystal is an object with translational symmetry. Basic research into and production of new materials necessitates the preparation of crystals of a particular morphology and with well-defined crystal defects. In this work, we found novel silica mesoporous crystal spheres with polyhedral hollows (icosahedral, such as those observed for proteins of virus capsids, decahedral, Wulff polyhedral, etc.) formed by the reverse multiply twinned bicontinuous double diamond mesostructure. Vesicles with a low-curvature lamellar structure were first formed by the self-assembly of amphiphilic carboxylic acid molecules in the presence of a nonionic surfactant and then underwent a structural transformation process that gave a reverse multiply twinned mesoporous shell while maintaining the hollow shape. These polyhedral hollow crystals showed an enhanced contrast of backscattering signatures relative to the incident acoustic signals and thus could be used as a potential contrast agent in medical ultrasonography with drug loadings in the mesopores.

Mesoporous silicas by self-assembly of lipid molecules : Ribbon, hollow sphere, and chiral materials

Using lipids (N-acyl amino acids) and 3-aminopropyltriethoxysilane as structure- and co-structure-directing agents, mesoporous silicas with four different morphologies, that is, helical ribbon (HR), hollow sphere, circular disk, and helical hexagonal rod, were synthesized just by changing the synthesis temperature from 0 degrees C to 10, 15, or 20 degrees C. The structures were studied by electron microscopy. It was found that 1) the structures have double-layer disordered mesopores in the HR, radially oriented mesopores in the hollow sphere, and highly ordered straight and chiral 2D-hexagonal mesopores in the disklike structure and helical rod, respectively; 2) these four types of mesoporous silica were transformed from the flat bilayered lipid ribbon with a chain-interdigitated layer phase through a solid-solid transformation for HR formation and a dissolving procedure transformation for the synthesis of the hollow sphere, circular disk, and twisted morphologies; 3) the mesoporous silica helical ribbon was exclusively right-handed and the 2D-hexagonal chiral mesoporous silica was excessively left-handed when the L-form N-acyl amino acid was used as the lipid template; 4) the HR was formed only by the chiral lipid molecules, whereas the 2D-hexagonal chiral mesoporous silicas were formed by chiral, achiral, and racemic lipids. Our findings give important information for the understanding of the formation of chiral materials at the molecular level and will facilitate a more efficient and systematic approach to the generation of rationalized chiral libraries.

pH-responsive mitoxantrone (MX) delivery using mesoporous silica nanoparticles (MSN)

The pH-responsive delivery of an anti-cancer drug, MX, has been successfully achieved by varying the strength of the electrostatic interaction between the negatively charged silicate and positively charged MX, using MSN.