Alternating Sulfone Copolymers Depolymerize in Response to Both Chemical and Mechanical Stimuli

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Stimuli-responsive polymers are crucial for signal amplification in sensing and drug delivery.
• Self-immolative polymers and polyaldehydes are examples of existing depolymerizable macromolecules.
• The development of novel depolymerizable polymers expands the toolkit for advanced material applications.

Purpose of the Study:

• To investigate the depolymerization of poly(vinyl acetate-alt-sulfur dioxide) (PVAS) initiated by chemical and mechanical stimuli.
• To explore the potential of PVAS as a stimuli-responsive material for drug delivery.
• To characterize the depolymerization kinetics and mechanisms of PVAS.

Main Methods:

• Synthesis of poly(vinyl acetate-alt-sulfur dioxide) copolymers.
• Exposure of PVAS to UV/acetone, various Reactive Oxygen Species (ROS), and ultrasonication.
• Kinetic studies to analyze depolymerization rates and mechanisms.
• Characterization of monomer production post-depolymerization.

Main Results:

• PVAS undergoes clean depolymerization into its monomer components upon exposure to UV/acetone, ROS, and ultrasonication.
• Depolymerization follows a two-part, first-order kinetic model with distinct initiation and propagation phases.
• Ultrasonication triggered depolymerization that continued even after the stimulus was removed.
• The polymer demonstrated reactivity to both oxidizing and radical-containing ROS.

Conclusions:

• Poly(vinyl acetate-alt-sulfur dioxide) is a novel class of stimuli-responsive polymers.
• PVAS can be depolymerized by a range of chemical and mechanical cues, including UV, ROS, and ultrasonication.
• These findings highlight the potential of PVAS for applications in drug delivery, responding to both endogenous and external stimuli.