Spontaneous and specific activation of chemical bonds in macromolecular fluids.
Mechanical activation of chemical bonds typically involves the application of external forces, which implies a broad distribution of bond tensions. We demonstrate that controlling the flow profile of a macromolecular fluid generates and delineates mechanical force concentration, enabling a hierarchical activation of chemical bonds on different length scales from the macroscopic to the molecular. Bond tension is spontaneously generated within brushlike macromolecules as they spread on a solid substrate. The molecular architecture creates an uneven distribution of tension in the covalent bonds, leading to spatially controlled bond scission. By controlling the flow rate and the gradient of the film pressure, one can sever the flowing macromolecules with high precision. Specific chemical bonds are activated within distinct macromolecules located in a defined area of a thin film. Furthermore, the flow-controlled loading rate enables quantitative analysis of the bond activation parameters.
Park
Insun
I
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Shirvanyants
David
D
Nese
Alper
A
Matyjaszewski
Krzysztof
K
Rubinstein
Michael
M
Sheiko
Sergei S
SS
D000179:Acrylates / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008567:Membranes, Artificial; D015394:Molecular Structure; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D013499:Surface Properties
D000179:Acrylates; D046911:Macromolecular Substances; D008567:Membranes, Artificial; D011108:Polymers; D011109:Polymethacrylic Acids; C498324:poly(n-butyl acrylate); C030613:polymethacrylic acid