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Molecular bridged silica aerogels have received extensive interest in recent years due to their easily controlled mechanical properties varying with different organosilane precursors, and without any further post-modification. In this work, a series of novel and robust molecular bridged silica aerogels were prepared by using a symmetrical urethane-bridged monomer, named N,N-bis(propyltriethoxysilyl)carbamide (bPTSCA), which was synthesized via a solvent-free exothermic reaction between 3-isocyanatopropyltriethoxysilane (IPTES) and 3-aminopropyltriethoxysilane (APTES) for several minutes at normal temperature and pressure. The influence of catalysts on the obtained gels and aerogels was studied in detail. It was found that NH4F aqueous solution showed the most effective catalysis capability, and the corresponding aerogels were intact with slight shrinkages. The mechanical strength of these aerogels could reach as high as 100 times more than that of the native silica aerogels (unbridged), and the strength could be easily adjusted from a rigid region to an elastic region simply by varying the sample density. Moreover, these aerogels possessed an interesting character of regional shrinking when encountering with water, which made it possible to fabricate artistic aerosculptures with water or other polar solvents as a graver.

The superhydrophobicity of living bodies such as lotus leaves, butterfly wings, and water strider legs has its own physiological meaning and it is critical for the survival of these lives. Although great progress has been achieved in superhydrophobic modification on a variety of substrates, such as glass, silicon wafer, and fabric, which are all lifeless objects, it is a great challenge for the superhydrophobic modification of living creatures. In this work, strategies to fulfill the vision are proposed by synthesis of a series of biocompatible silica aerogel microparticles via a solvent-exchange-free and ambient pressure drying process. Then, dry-painting of the aerogel microparticles directly on various surfaces is developed. Interestingly, the results indicate that the silica aerogel microparticles can not only be successfully applied to various lifeless surfaces (e.g., glass, paper, and polymers), but also be used on biotic surfaces of living bodies (e.g., leaves, flowers, and skin). Moreover, these superhydrophobic coatings are mechanically stable but could be easily removed on demand by simple methods due to the non-covalent bonding between the aerogel and the substrates. Ultimately, an “invisible glove” is also demonstrated by the fact that nothing is hurt after dipping hands daubed with the SHB-SAMPs into highly corrosive aqueous liquids, e.g., 1 M HCl and 1 M NaOH.

Three poly(ethylene glycol)–poly(e-carprolactone) (PEG–PCL) copolymers with different topologies but identical molar ratio between PEG to PCL were designed. These copolymers, namely, diblock (L-PEG–PCL), triblock (B-PEG–PCL), and star shaped (S-PEG–PCL) copolymers, were extensively characterized by 1H Nuclear Magnetic Resonance (1H NMR), Fourier Transform Infrared Spectroscopy (FTIR), and Gel Permeation Chromatography (GPC) analyses. The effect of topology on crystallization was investigated by X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC). Results showed that the diblock copolymer possessed the highest crystallinity, followed by triblock and star shaped copolymers. Although the topology did not affect the self-assembly behavior of copolymers, the effects on size, size distribution, drug loading content, and drug release rate of the polymeric micelles were observed. The micelles self-assembled from linear diblock copolymer achieved higher cellular uptake and lower half maximal inhibitory concentration (IC50). These findings are favorable to establish the foundation to further design proper structure of amphiphilic copolymers as nanocarrier systems for efficient anticancer therapy.

Porous silica films with a refractive index varying from 1.44 to 1.15 were prepared and applied to realize a double-layer broadband AR coating. The porous silica films were obtained using tetraethylorthosilicate (TEOS) as precursor and a binary template as porogen which was composed of cetyltrimethylammonium bromide (CTAB) and polypropylene glycol (PPG). The molar ratio of the two templates was optimized, and a hypothetical mechanism for the cooperative assembly of silicates with the binary template system was proposed. The two layers had the same skeleton despite different porosity with the top layer much more porous than the bottom one. The double-layer double-wavelength AR coating had excellent optical properties with transmittances of 99.6% and 99.8% at 532 nm and 1064 nm, respectively.

In this study, molecular-bridged silica aerogels (MBSAs) were synthesized via supercritical CO2 liquid drying of bridged 3-aminopropyltriethoxysilane (APTES) wet gels, which were autocatalytic gelled by the catalyst-free bridging of APTES and 1,4-phthalaldehyde via a Schiff base condensation. The detailed mechanism of this facile, one-pot and autocatalytic approach for the production of MBSAs was revealed by in situ 1H NMR and FTIR measurements, and the critical conditions for the successful autocatalytic gelation of the bridged-APTES were investigated. The densities and average pore diameters were in the range from 0.0535 to 0.0702 g cm−3 and from 12.9 to 14.1 nm, respectively. Moreover, the morphologies and thermal stability of the products were characterized by SEM and TGA, respectively. Interestingly, the MBSAs show excellent absorption performance for organic solvents, e.g., hexane, dichloromethane, kerosene, dimethylsulfoxide, tetrahydrofuran, ethanol, ethylsilicate, and N,N-dimethylformamide. Among those, 2437% by mass absorption of dichloromethane was achieved. Moreover, the absorption property of the aerogel was stable, with nearly no deterioration even after 30 absorption–desorption cycles. In addition, the aerogel showed remarkable flexibility, with the highest deformation of 90% and complete recovery after the release of stress, and it can be under through 30 cycles of compression–reversion process with 40% deformation.

Polydimethylsiloxane (PDMS)–silica ORMOSIL (organically modified silicate) sols were prepared by a one-pot sol–gel process using tetraethyl orthosilicate as an inorganic precursor and hydroxyl-terminated PDMS as an organic modifier, and antireflective (AR) coatings were prepared with these sols by dip coating. It was found that the addition of PDMS to silica sols significantly increased the viscosity and the controllable viscosity range of the silica sols, affording us a simple route to prepare very thick AR coatings with controlled thickness by a single deposition step. The coated fused silica substrates retained very high transmission of up to 99.9% at a determined wavelength. The addition of PDMS to the silica sols improved the hydrophobicity and abrasion-resistance of the coating, and prevented to some extent the coating from cracking which occurred in a pure inorganic thick AR coating. The PDMS–silica ORMOSIL AR coatings are stable after standing for 2 months at room temperature in an environment of 95% relative humidity. The relationship between structure and properties of the coatings is discussed considering the particle growth mechanism.