Polymer semiconductors — materials that are fabricated to be soft and elastic along with being able to conduct electricity — are potential candidates for future electronics that can be integrated within the body, such as health monitors and disease detectors.
Engineers and researchers, until now, were unable to bestow certain progressive features, like the capability to sense biochemicals, onto the polymers without disrupting their functionality.
Scientists at the Pritzker School of Molecular Engineering (PME) created a novel approach to overcome the limitation. The approach named “click-to-polymer,” or CLIP, involves a chemical reaction to bind new functional units onto polymer semiconductors.
The new approach was used by the scientists to create a polymer glucose monitoring device, indicating the viable applications of CLIP in human-integrated electronics. The research outcomes were published on August 4th, 2021, in Matter.
Semiconducting polymers are one of the most promising materials systems for wearable and implantable electronics. But we still need to add more functionality to be able to collect signals and administer therapies. Our method can work broadly to incorporate different types of functional groups, which we hope will lead to far-reaching leaps in the field.
Sihong Wang, Study Lead and Assistant Professor, Pritzker School of Molecular Engineering, The University of Chicago
Functionalizing Polymers Without Wecreasing their Efficacy
Several researchers earlier tried to achieve the new functionalities of these semiconducting polymers — also called conjugated polymers — by making them from scratch by including advanced features into the molecular designs directly.
However, traditional methods for achieving this were unsuccessful either because the molecules could not withstand the conditions needed to bind them to the polymer chains, or because the synthesis process decreased their efficacy.
To address this, Wang, along with graduate student Nan Li, created the CLIP method, which employs a copper-catalyzed azide-alkyne cycloaddition to provide functional units to a polymer. As this “click reaction” occurs after the creation of the polymer, it does not affect its initial properties greatly.
Along with that, the reaction can be used in bulk functionalization of the polymer and in surface functionalization — both vital for creating functional electronics.
A Potentially Game-Changing System
To establish the efficiency of CLIP, the scientists linked units that could photo-pattern the polymer, significant for designing circuits within the material. The researchers also introduced functionality to directly sense biomolecules. Their biomolecule sensor employed a glucose oxidase enzyme to detect glucose, which later causes changes to the polymer’s electrical conductance and amplifies the signal.
The researchers are now introducing other bio-active and biocompatible functionalities to these polymers, which Li states “has the potential of becoming a game-changing technology.”
We hope researchers across the field will use our method to endow even more functionality into this material system and use them to develop the next generation of human-integrated electronics as a key tool in healthcare.
Sihong Wang, Assistant Professor, Pritzker School of Molecular Engineering, The University of Chicago
Li, N., et al. (2021) A universal and facile approach for building multifunctional conjugated polymers for human-integrated electronics. Matter. doi.org/10.1016/j.matt.2021.07.013.