Thin Polymer Film Force Spectroscopy: Single Chain Pull-out and Desorption

Abstract

Atomic force microscopy (AFM) was utilized to investigate the force associated with chain pull-out and single chain desorption of poly(styrene-co-butadiene) random copolymer thin films on mica, silicon and graphite substrates. Chain pull-out events were common and produced a force of 20 -25 pN. The polymer desorption force was strongest on the graphite substrate and weakest on the mica, which agreed with the calculated work of adhesion for each system and the substrate hydrophobicity. Furthermore, it was demonstrated that there was a systematic order to when each of these phenomena occurred during the tip retraction from the surface, which provided information about the structure of the thin films.This material is available free of charge via the Internet at http://pubs.acs.org.

Solvent effects on surface-grafted and solution-born poly[N-(2-hydroxypropyl)methacrylamide] during surface-initiated RAFT polymerization

“…S4-S7, ESI †). 10,33,65 Increasing water content in the polymerization mixture leads to increased M n, sur , in agreement with the faster propagation observed in solution (see Table S3, ESI †), however, M n, sur showed a decreased propagation rate at condition DMF 25% compared to DMF 50%. This could be caused by mass transfer limitations: the propagation rate increases both in solution and on the surface, but the high local concentration of growing polymer chains on the surface rapidly depletes the monomer concentration in the interface region.…”

Surface Nanopatterning Using the Self-Assembly of Linear Polymers on Surfaces after Solvent Evaporation

“…Depending on the physicochemical properties of the polymers used, the resulting polymer-modified surface can impart many new properties and have a wide range of interesting applications. Over the last decades, polymer monolayers have been used in diverse areas such as colloidal stability [1][2][3], surface nanopatterning [4][5][6], adhesion [7][8][9], and tribology [10][11][12]. They can be formed by chemisorption/grafting chains (strong anchoring by covalent bonds) or by physisorption (weak chain attachment by van der Waals interactions) on appropriate substrates where (in principle) all monomers of the chains can be adsorbed on the substrate in the same way.…”

Manipulation of a Single Polymer Chain: From the Nanomechanical Properties to Dynamic Structure Evolution

“…In addition, the study of polymer interactions in the pure amorphous phase and the correlation of polymer interactions with the mechanical properties of the amorphous phase would also be quite interesting and challenging. To address these issues, the combination of the SMFS experiment with the theoretical simulations, such as the steered molecular dynamic simulations, 66 would be very necessary. Furthermore, the combination of SMFS with super-resolution fluorescence imaging 138 will also be quite helpful in this regard.…”

“…AFM-SMFS has been successfully used for the study of isolated single molecules in dilute solution and provided precise force and structure information. , However, it is challenging to assess single chain mechanics in condensed state. To establish the relationship between structure and single-chain mechanics in condensed polymer systems, and also to extract chain folding (or chain trajectory) information on single-chain level, we established a new method that combines AFM imaging and SMFS in situ.…”