Designing plastics that can be broken down easily after their use phase have often required a trade-off between stability and ease of deconstruction. Recent research by scientists at Rutgers University (New Brunswick, N.J.; www.rutgers.edu) opens a path to resolve that trade-off — polymers designed to self-deconstruct via breakdown mechanisms with programmable rates.
Self-deconstruction of biopolymers, such as proteins and nucleic acids, under mild conditions is common in nature, but has generally been underutilized for synthetic polymers. The Rutgers team, led by Yuwei Gu, developed a process for “conformational preorganization” of polymer chains to enable modulated breakdown of the plastics on-demand and at tunable rates. Inspired by principles observed in natural biopolymer self-deconstruction, the researchers designed “scaffolds that covalently preorganize hydroxy groups relative to phosphotriester groups along the polymer backbone.”
This strategy of spatially orienting the hydroxy groups relative to the phosphotriester deconstruction sites is a key aspect of the design of degradable polymers. “Self-deconstruction can be reversibly switched on or off by controlling polymer folding through metal–polyether coordination,” the researchers write, “which conformationally aligns distal hydroxy groups with deconstruction sites.”
Source: Rutgers
Not only does their advance make plastics more degradable, but also makes this process programmable. Gu says the project focused on “making these bonds easier to break when needed, without weakening the material during use.”
By engineering the arrangement of polymer structure, the plastic can break down at rates that are several orders of magnitude faster than normal, but only when triggered. Gu points out that introducing co-monomers with the required chemistry to initiate the polymer breakdown in does not materially affect the plastic’s properties in use. By controlling the positioning and orientation of the co-monomers, “we can engineer the same plastic to break down over days, months or even years,” Gu says, matching the plastic lifetime to its purpose.
The implications of the research go beyond addressing global plastic issues. Gu says these principles of polymer engineering could enable timed drug-release capsules and self-erasing coatings, for example. “This research not only opens the door to more environmentally responsible plastics but also broadens the toolbox for designing smart, responsive polymer-based materials across many fields,” he said.
The research was published in a recent issue of Nature Chemistry.