From force pattern to interfacial conformation

COLL 453

Xi Zhang, Department of Chemistry, Department of Chemistry, Jilin University, Jiefang Road 119, Changchun 130023, China
AFM based single-molecule force spectroscopy(SMFS) has been proven to be a versatile platform for investigating interolecular and intramolecular interaction in macromolecular systems, leading to opening a new field of nano-mechanics of macromolecules. Using SMFS, we will discuss the detachment of macromolecules from the substrates, focusing on detecting the desorption forces and revealing macromolecular conformation at inteface. Firstly, utilizing the defects of self-assembled monolayers, we propose a simple method to isolate single macromolecule for direct measurement of the desorption force of polyelectrolytes from substrates. Secondly,we have studied the selective adsorption of segmented poly(N-isopropylacrylamide-seg-styrene)copolymer on either hydrophobic or hydrophilic substrate. Based on the careful analysis of force patterns, we are able to reveal the formation of regular loops at interface, and even more, to directly measure the hydrophobic interaction per styrene segment from polystyrene substrate.