Silver nanoparticles (NPs)/chitosan nanofibers (ChNF) composite material was fabricated using a high-pressure wet-type jet mill. A mixture comprising an aqueous silver nitrate solution and a ChNF suspension was prepared as a starting material. The mixture was then processed using the high-pressure wet-type jet mill at a discharge pressure of 100 MPa. X-ray diffraction analysis of the obtained samples revealed the presence of not only chitosan crystallites, but also silver metal crystallites. According to field-emission scanning electron microscopy observation, many nano-sized silver particles were immobilized and well-dispersed on the surface of ChNF. The silver NPs had a spherical shape with an average particle size of about 20 nm regardless of the number of jet milling cycles. The silver content in the composite materials increased slightly with the number of jet milling cycles. As a result of investigating the antibacterial properties of the silver NPs/ChNF composite material that is processed five times with the high-pressure wet-type jet mill at a discharge pressure of 100 MPa, it was found that the minimum inhibitory concentration (MIC) of that for E. coli was 4.2 mg/L, although raw ChNF had no antibacterial properties.

Silver nanoparticles (AgNPs) on the surface of cellulose nanofibers (CNF) were immobilized using a high-pressure wet-type jet mill to increase their stability while maintaining their catalytic activity. As a raw starting material, an aqueous silver nitrate solution was mixed with a CNF suspension. The mixture was then processed five times using the high-pressure wet-type jet mill at a discharge pressure of 100 MPa. AgNPs with an average particle size of 3.8 « 0.8 nm were immobilized and well-dispersed on the surface of CNF, as observed by transmission electron microscopy. The catalytic activities of the AgNPs coated with PVP (AgPVP) and the prepared AgNPs-supported on CNF composite (AgCNF) were evaluated. As a result, the catalytic activity of AgCNF was discovered to be 2.32 times greater than that of AgPVP. The catalytic activity was measured in terms of the number of runs because AgCNF can be easily recovered by centrifugation or filtration. Even the catalytic activity of AgCNF after five runs was maintained at 62%, but the catalytic activity gradually decreased as the number of runs increased.

Silver nanoparticles (NPs) / chitosan nanofibers (ChNF) composite material was fabricated with a highpressure wet-type jet mill. A mixture comprising an aqueous silver nitrate solution and a ChNF suspension was prepared as a raw starting material. The mixture was then processed with the high-pressure wet-type jet mill at a discharge pressure of 100 MPa. An X-ray diffraction analysis of the obtained samples revealed the presence of not only chitosan crystallites, but also silver metal crystallites. According to field-emission scanning electron microscopy observation, many nano-sized silver particles were immobilized and well-dispersed on the surface of ChNF. The silver particles had a spherical shape with an average particles size of about 20 nm regardless of the number of jet milling cycles. The silver content in the composite materials increased slightly with the number of jet milling cycles. As a result of investigating the antibacterial property of the silver NPs /ChNF composite material processed five times with the high-pressure wet-type jet mill at a discharge pressure of 100 MPa, it was found that the minimum inhibitory concentration (MIC) of that for E. coli was 4.2 mg/L, although a raw ChNF had no antibacterial property.