title: Macroporous silicon templated from silicon nanocrystallite and functionalized Si-H reactive group for grafting organic monolayer.
abstract: This paper reports the development of a new fabrication process for highly porous and highly functional macroporous silicon (m-PSi). This new fabrication process involves two steps of electrochemical etching and one step of sonication detachment, and it uses silicon nanocrystallites as a template to form a honeycomb-like macroporous structure. The surface fabricated by this process has been characterized in comparison with the m-PSi surface fabricated by a one-step etching process. Scanning electron microscopy (SEM) images show that both m-PSi surfaces have nearly similar pore diameters (1-2 microm), but their porous microstructures are very different: the surface fabricated by two-step etching exhibits a smooth and shallow pore structure, while the other surface exhibits a rough and deep pore structure. Fourier transform infrared spectroscopy (FTIR) analyses reveal that the former is functionalized with a reactive Si-H group, while the latter is functionalized with a stable Si-O-Si group. To evaluate the Si-H reactive group, an allyl polyethylene glycol (PEG) is employed to modify the surface through hydrosilylation. SEM, FTIR, X-ray photoelectron spectroscopy, and water contact angle measurements are used to characterize the PEG-grafted m-PSi surface. PEG-grafted m-PSi substrates may have wide applications in biosensors, chemosensors, and biochips.
authors.affiliation: Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China. dongjie.guo@colorado.edu
authors.forename: Dong-Jie
authors.initials: DJ
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Tan
authors.forename: Shou-Jun
authors.initials: SJ
authors.lastname: Xiao
authors.forename: Zhen-Dong
authors.initials: ZD
authors.lastname: Dai
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004563:Electrochemistry; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D017655:Silicon Compounds; D011092:Polyethylene Glycols; D012825:Silicon