Self-healing supramolecular polymers in action

\u3cp\u3eSophisticated polymeric materials with responsive properties, such as self-healing, are beginning to reach the market. Supramolecular polymers, i.e., polymers that owe their mechanical properties primarily to the reversible, non-covalent interactions, such as hydrogen bonding interactions, between the macromolecules, have frequently been employed as self-healing materials. The quadruple hydrogen bonding ureidopyrimidinone (UPy) unit is a particularly effective and versatile design motif, since it forms very strong but reversible linkages, and can be incorporated into virtually any type of polymer backbone, leading to materials with increased mechanical properties. Supramolecular polymers are presented, with an emphasis on those based on the UPy-unit, and their use in self-healing applications is highlighted and discussed. Supramolecular polymers are eminently useful in self-healing applications. The reversible nature of supramolecular polymers allows for self-healing processes to take place, using a contact pressure trigger or a heat trigger. Several materials are presented with an emphasis on ureidopyrimidinone (UPy) comprising supramolecular polymer.\u3c/p\u3

Siloxane polymers with quadruple hydrogen bonding units

The invention relates to the synthesis of siloxane polymers containing self-complementary quadruple hydrogen bonding groups (4H-units). The resulting polymers show unique new characteristics that result from the reversible, physical interactions between the polysiloxane chains that are based on the (supramolecular) interactions between the 4H-units. The polysiloxanes in this invention show unprecedented bulk material properties and are used as gelling agents for silicone fluids. The resulting gels are clear and display good material properties, while having unparalleled high silicone fluid contents

Preparation of supramolecular polymers by copolymerization of monomers containing quadruple hydrogen bonding units with regular monomers

The invention relates to the synthesis of polymers contg. self-complementary quadruple H groups by copolymg. monomers contg. a quadruple H bonding group with ³1 monomers of choice. The resulting polymers show unique new characteristics due to the presence of addnl. phys. interactions between the polymer chains that are based on multiple H bonding interactions (supramol. interactions). Thus, 2-isocyanatoethyl methacrylate (7.0 mL) was added to a soln. of 6-(1-ethylpentyl)isocytosine (13.4 g) in dry pyridine (150 mL), the reaction mixt. was stirred under Ar at 80° for 4 h to give a monomer, and was polymerizable with 2-hydroxyethyl methacrylate in the presence of ATRP initiators, CuBr, and bipyridine

Development and in-vivo characterization of supramolecular hydrogels for intrarenal drug delivery

Intrarenal drug delivery from a hydrogel carrier implanted under the kidney capsule is an innovative way to induce kidney tissue regeneration and/or prevent kidney inflammation or fibrosis. We report here on the development of supramolecular hydrogels for this application. We have synthesized two types of supramolecular hydrogelators by connecting the hydrogen bonding moieties to poly(ethylene glycols) in two different ways in order to obtain hydrogels with different physico-chemical properties. Chain-extended hydrogelators containing hydrogen bonding units in the main chain, and bifunctional hydrogelators end-functionalized with hydrogen bonding moieties, were made. The influence of these hydrogels on the renal cortex when implanted under the kidney capsule was studied. The overall tissue response to these hydrogels was found to be mild, and minimal damage to the cortex was observed, using the infiltration of macrophages, formation of myofibroblasts, and the deposition of collagen III as relevant read-out parameters. Differences in tissue response to these hydrogels could be related to the different physico-chemical properties of the three hydrogels. The strong, flexible and slow eroding chain-extended hydrogels are proposed to be suitable for long-term intrarenal delivery of organic drugs, while the weaker, soft and fast eroding bifunctional hydrogel is eminently suitable for short-term, fast delivery of protein drugs to the kidney cortex. The favourable biological behaviour of the supramolecular hydrogels makes them exquisite candidates for subcapsular drug delivery, and paves the way to various opportunities for intrarenal therapy. © 2012 Elsevier Ltd