Mechanically Gated Degradable Polymers.


Journal Article

Degradable polymers are desirable for the replacement of conventional organic polymers that persist in the environment, but they often suffer from the unintentional scission of the degradable functionalities on the polymer backbone, which diminishes polymer properties during storage and regular use. Herein, we report a strategy that combats unintended degradation in polymers by combining two common degradation stimuli-mechanical and acid triggers-in an "AND gate" fashion. A cyclobutane (CB) mechanophore is used as a mechanical gate to regulate an acid-sensitive ketal that has been widely employed in acid degradable polymers. This gated ketal is further incorporated into the polymer backbone. In the presence of an acid trigger alone, the pristine polymer retains its backbone integrity, and delivering high mechanical forces alone by ultrasonication degrades the polymer to an apparent limiting molecular weight of 28 kDa. The sequential treatment of ultrasonication followed by acid, however, leads to a further 11-fold decrease in molecular weight to 2.5 kDa. Experimental and computational evidence further indicate that the ungated ketal possesses mechanical strength that is commensurate with the conventional polymer backbones. Single molecule force spectroscopy (SMFS) reveals that the force necessary to activate the CB molecular gate on the time scale of 100 ms is approximately 2 nN.

Full Text

Duke Authors

Cited Authors

  • Lin, Y; Kouznetsova, TB; Craig, SL

Published Date

  • February 2020

Published In

Volume / Issue

  • 142 / 5

Start / End Page

  • 2105 - 2109

PubMed ID

  • 31939656

Pubmed Central ID

  • 31939656

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/jacs.9b13359


  • eng