| Nanotechnology has gained its prosperity in the past two decades because of extensive contributions from interdisciplinary collaboration and a favorable interaction with practical applications. It covers a huge spectrum of applications. The dissertation hereby, in conjunction with the three research projects conducted by the author, will make contributions to nanotechnology applications in the following three topics: biomass pretreatment in biofuel production, functional material fabrication and surface modification.;First, a fast and efficient nano-scale shear hybrid alkaline (NSHA) pretreatment method of lignocellulosic biomass was introduced. In this work, corn stover was pretreated in a modified Taylor-Couette reactor with sodium hydroxide at room temperature, with a two-minute retention time and a 12500 s -1 shear rate. Synergistic effects induced by the NSHA pretreatment disrupted the naturally-formed recalcitrance of biomass and generated nano-scale polysaccharide aggregates that are ready to be digested. After the pretreatment, results revealed major removals of hemicellulose and lignin, leaving an up to 82 % of cellulose content in the remaining solid. Compared with untreated corn stover, an approximately 4-fold increase in enzymatic cellulose conversion and a 5-fold increase in hemicellulose conversion were achieved.;Second, a nano-deposition strategy was developed to enhance the energy absorption capacity of aluminum (Al) open-cell foams. The energy absorption capacity of open cell foams can be enhanced by a homogeneous thickening of the foam struts. However, the enhancement is compromised since an increase in the plateau stress without a reduction in densification strain cannot be achieved. To overcome that problem, a featured non-cyanide nano-crystalline copper electro-deposition system was setup for the coating of open-cell Al foam, and, the energy absorption capacity as a function of foam pore size and Cu coating thickness was investigated. An up to 3-time enhancement was achieved with a 60 microm Cu coating on Al foams with an average strut thickness of 192 microm. The compressive stress-strain response of the composite samples showed no significant reduction of the densification strain compared to the uncoated foams. With the same overall strut thickness, nano-reinforced foams had superior energy absorption capacity over plain foams, with almost a 2-time enhancement.;Finally, a facile "dip & rinse" method for nickel (Ni) electroless deposition on hydrophobic polymer surfaces was developed. The electroless deposition (metallization) usually incorporates a harsh and/or toxic surface conditioning to activate the substrate. To eliminate the need for that step, a facile method of electroless Ni deposition on various hydrophobic polymer substrates was demonstrated, by making use of the hydrophobic interactions between Poly(allylamine hydrochloride) (PAH) and polymer substrates for catalyst adsorption/immobilization. Various hydrophobic polymer surfaces with different geometries and dimensions, including low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP) and polystyrene (PS) thin sheets, and PE pellets were tested and Ni was successfully deposited onto all these surfaces. A kinetic study on polymer thin sheets examples showed that with 2 hours of deposition, an approximately 2 microm thickness was achieved. A prove-of-concept study showed that Ni coated polymer thin sheets can be further electrodeposited with heterogeneous metal (Cu), hence enabling a faster thickness growth over time. |
