Weili Hu

Flexible electrically conductive nanocomposite membrane based on bacterial cellulose and polyaniline.

The novel conductive polyaniline/bacterial cellulose (PANI/BC) nanocomposite membranes have been synthesized in situ by oxidative polymerization of aniline with ammonium persulfate as an oxidant and BC as a template. The resulting PANI-coated BC nanofibrils formed a uniform and flexible membrane. It was found that the PANI nanoparticles deposited on the surface of BC connected to form a continuous nanosheath by taking along the BC template, which greatly increases the thermal stability of BC. The content of PANI and the electrical conductivity of composites increased with increasing reaction time from 30 to 90 min, while the conductivity decreased because of the aggregation of PANI particles by further prolonging the reaction time. In addition, the acids remarkably improve the accessibility and reactivity of the hydroxyl groups of BC. The results indicate that the composites exhibit excellent electrical conductivity (the highest value was 5.0 × 10(-2) S/cm) and good mechanical properties (Youngs modulus was 5.6 GPa and tensile strength was 95.7 MPa). Moreover, the electrical conductivity of the membrane is sensitive to the strain. This work provides a straightforward method to prepare flexible films with high conductivity and good mechanical properties, which could be applied in sensors, flexible electrodes, and flexible displays. It also opens a new field of potential applications of BC materials.

Functionalized bacterial cellulose derivatives and nanocomposites.

Bacterial cellulose (BC) is a fascinating and renewable natural nanomaterial characterized by favorable properties such as remarkable mechanical properties, porosity, water absorbency, moldability, biodegradability and excellent biological affinity. Intensive research and exploration in the past few decades on BC nanomaterials mainly focused on their biosynthetic process to achieve the low-cost preparation and application in medical, food, advanced acoustic diaphragms, and other fields. These investigations have led to the emergence of more diverse potential applications exploiting the functionality of BC nanomaterials. This review gives a summary of construction strategies including biosynthetic modification, chemical modification, and different in situ and ex situ patterns of functionalization for the preparation of advanced BC-based functional nanomaterials. The major studies being directed toward elaborate designs of highly functionalized material systems for many-faceted prospective applications. Simple biosynthetic or chemical modification on BC surface can improve its compatibility with different matrix and expand its utilization in nano-related applications. Moreover, based on the construction strategies of functional nanomaterial system, different guest substrates including small molecules, inorganic nanoparticles or nanowires, and polymers can be incorporated onto the surfaces of BC nanofibers to prepare various functional nanocomposites with outstanding properties, or significantly improved physicochemical, catalytic, optoelectronic, as well as magnetic properties. We focus on the preparation methods, formation mechanisms, and unique performances of the different BC derivatives or BC-based nanocomposites. The special applications of the advanced BC-based functional nanomaterials, such as sensors, photocatalytic nanomaterials, optoelectronic devices, and magnetically responsive membranes are also critically and comprehensively reviewed.

Polyol mediated synthesis of ZnO nanoparticles templated by bacterial cellulose

Zinc oxide nanoparticles have been successfully synthesized through a facile polyol method using bacterial cellulose (BC) as a template. BC membrane was used as a host matrix to introduce quantitatively Zn(2+) ions and then as nanoreactors to fabricate ZnO nanoparticles by hydrolysis of zinc acetate in a polyol medium. The influence of the concentration of zinc acetate and hydrolytic time on the morphologies and size of ZnO nanoparticles were investigated. The results indicated that the uniform spherical ZnO nanoparticles were incorporated into BC fibers. The resulting nanocomposites show good mechanical properties and high photocatalytic activity in the degradation of methyl orange.

High photocatalytic properties of zinc oxide nanoparticles with amidoximated bacterial cellulose nanofibers as templates

The freshly prepared water-wet amidoximated bacterial cellulose (Am-BC) serves as an effective nanoreactor to synthesis zinc oxide nanoparticles by in situ polyol method. The obtained ZnO/Am-BC nanocomposites have been characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The influence of the zinc acetate concentration on the morphologies and size of ZnO nanoparticles and the possible formation mechanism were discussed. The results indicated that uniform ZnO nanoparticles were homogeneously anchored on the Am-BC nanofibers through strong interaction between the hydroxyl and amino groups of Am-BC and ZnO nanoparticles. The loading content of ZnO nanoparticles is higher using Am-BC as a template than using the unmodified bacterial cellulose. The resultant nanocomposite synthesized at 0.05 wt% shows a high photocatalytic activity (92%) in the degradation of methyl orange.