Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential | Moores et al. Nanoscale Research Letters 2011 6 185 http content 6 1 185 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential Bradley Moores1 Janet Simons2 Song Xu3 Zoya Leonenko1 2 Abstract Thiol self-assembled monolayers SAMs are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy AFM and Kelvin probe force microscopy KPFM . We produced SAMs-patterns made of alternating positively charged negatively charged and hydrophobic-terminated thiols by an automated AFM-assisted manipulation or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM and distinguished differences in surface potential 20-50 mV revealed by KPFM. The pattern can be helpful in the development of biosensor technologies specifically for selective binding of biomolecules based on charge and hydrophobicity and serve as a model for creating surfaces with quantified alternating surface potential distribution. Background Thiol self-assembled monolayers SAMs are promising for many nano- and bio-technology applications as they offer a reliable method to produce surfaces with desirable properties. These properties can be used for specific and non-specific binding of biomolecules and nanoparticles and therefore can serve as useful templates for nano- and micro-fabrication. The first systematic study of thiol chemicals was reported by Zisman and coauthors 1 and has since been investigated by many researchers including a detailed review by Chechik et al 2 . SAMs can be defined as molecular assemblies that are formed spontaneously be the immersion of an appropriate substrate into a solution of an active surfactant in an organic solvent 3 . Thiols
