University of Illinois

Hanze Ying

Jianjun Cheng

John A Rogers

SukWon Hwang

Yanfeng Zhang

Seung-Kyun Kang

Kaimin Cai

The present invention relates to polymers having dynamic urea bonds and more specifically to polymers having hindered urea bonds (HUBs) with fast hydrolytic kinetics. These urea bonds are aryl-substituted, i.e. aromatic-substituted hindered urea bonds, that demonstrate pH independent hydrolytic kinetics, such that they consistently and rapidly hydrolyze in water from pH 2 to 11. The urea bond dissociation for these materials is generally such that k&#x3e;h, which is two orders of magnitudes faster than for aliphatic hindered ureas. The present invention also relates to hydrolytically reversible or degradable linear, branched or network polymers incorporating these HUBs and to precursors for incorporation of these HUBs into these polymers. The technology can be applied to and integrated into a variety of polymers, such as polyureas, polyurethanes, polyesters, polyamides, polycarbonates, polyamines, and polysaccharides to make linear, branched, and cross-linked polymers. Polymers incorporating these HUBs can be used in a wide variety of applications including for example, environmentally compatible packaging materials and biomedical applications, such as drug delivery systems and tissue engineering. In other embodiments, the HUBs can be used in self-healing polymers.

Dynamic urea bonds with fast hydrolytic kinetics for polymers

The present invention relates to a one-component processing method and system for preparing polyurea materials. This method and system involves a polymerization process using cyclic oligomeric polyurea precursors. These cyclic oligomeric precursors have dynamic urea bonds such as hindered urea bonds (HUBs). These cyclic oligomeric precursors exhibit dynamic properties to reversibly dissociateyielding isocyanate and amine components which polymerize to yield the polyureas, such as linear, branched or cross-linked polyureas. This method and system has advantages over conventional methods that utilize two-component systems. Such two-component systems require the segregation of the isocyanate and amine components to prevent premature or too rapid polymerization. The resulting polyureas are useful for a variety of applications including coatings.

Cyclic dynamic polyureas for polymeric urea processing

The invention provides transient devices, including active and passive devices that physically, chemically and/or electrically transform upon application of at least one internal and/or external stimulus. Incorporation of degradable device components, degradable substrates and/or degradable encapsulating materials each having a programmable, controllable and/or selectable degradation rate provides a means of transforming the device. In some embodiments, for example, transient devices of the invention combine degradable high performance single crystalline inorganic materials with selectively removable substrates and/or encapsulants.

Transient electronic devices comprising inorganic or hybrid inorganic and organic substrates and encapsulates

The disclosure provides reversible polymers from polyurea by modifying the nitrogen atom with hindered substituents. The reversibility of hindered urea bond (HUB) can be controlled by changing the bulkiness of the substituents, and N-tert-butyl-N-ethylurea (TBEU), with its high binding constant and short lifetime, is applicable in the design of reversible polymer and self-healing materials at mild temperatures without external stimuli. HUB can be used in the design of smart materials with its adjustable reversibility, facile synthesis, and compatibility with many other polymer structures.

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Champaign, IL, United States of America

Hanze Ying