Soft matter with intelligence

 

We are developing a range of responsive dynamic soft gel-based materials for advanced delivery systems, rheology modifiers, and soft robotics. Recent examples are our hydrogel objects which can show programmed independent responsive behavior and communication, and our development of our moldable responsive HIPE-gel objects and fibers. 

 

 
The independent action of fibres of different compositions in a closed system.  Three populations of fibres can be seen: 10 g/L (red), 8 g/L (blue) and 4 g/L (orange). Fibres of a higher enzyme concentration start to disassemble before those of a lower concentration. At the beginning, all fibres are intact. After 78 seconds, only the red fibres have released their oil droplets. After 614 seconds, the blue fibres have released their droplets and after 1030 seconds, the orange fibres have released theirs. Scale bar = 1 cm.

The independent action of fibres of different compositions in a closed system. Three populations of fibres can be seen: 10 g/L (red), 8 g/L (blue) and 4 g/L (orange). Fibres of a higher enzyme concentration start to disassemble before those of a lower concentration. At the beginning, all fibres are intact. After 78 seconds, only the red fibres have released their oil droplets. After 614 seconds, the blue fibres have released their droplets and after 1030 seconds, the orange fibres have released theirs. Scale bar = 1 cm.

In our 2017 Materials Horizons paper we show the fabrication of soft hydrogel alginate-based objects, namely fibres and beads, that have an individually programmed time delay in their response to a shared environmental stimulus. We utilize the enzyme urease to programme a self-regulated change in pH, which in turn activates the designed response of gel fibre disintegration or a change in gel beads colour. This design allows for independent response behaviour of a collection of bodies in a single closed system, as well as inter-material communication on shorter length scales. The incorporation of responsive time control directly into soft matter objects demonstrates an advance in the field of autonomous materials. You can read the paper here: http://dx.doi.org/10.1039/C7MH00033B

 

   In our  2016   Journal of Materials Chemistry A  paper we show that emulsion droplets stabilized by branched copolymers and Laponite clay discs can be assembled into supracolloidal fibers with control of the fiber composition and length. We call these fibers HIPE (high internal phase emulsion) fibers and they are composed of thousands if not millions of emulsion droplets. Upon drying they transform into a light-weight highly porous nanocomposite material. We demonstrate that the fibers made from emulsion droplets can be used to release volatile compounds in a time-controlled manner. More on our  blog . You can read the (open access) paper here:  http://dx.doi.org/10.1039/C5TA08917D

 

In our 2016 Journal of Materials Chemistry A paper we show that emulsion droplets stabilized by branched copolymers and Laponite clay discs can be assembled into supracolloidal fibers with control of the fiber composition and length. We call these fibers HIPE (high internal phase emulsion) fibers and they are composed of thousands if not millions of emulsion droplets. Upon drying they transform into a light-weight highly porous nanocomposite material. We demonstrate that the fibers made from emulsion droplets can be used to release volatile compounds in a time-controlled manner. More on our blog. You can read the (open access) paper here: http://dx.doi.org/10.1039/C5TA08917D

In our  2013   Chemical Communications  paper we report the fabrication of various shaped High Internal Phase Emulsion hydrogels. Key is the use of dilute waterborne poly( N -isopropylacrylamide) microgel dispersions which are non-covalently crosslinked through 2-ureido-4[1H] pyrimidinone (UPy) quadruple hydrogen bond groups. These microgels were developed in one of our earlier papers published in  2013  in  Polymer Chemistry  (read the paper here:  http://dx.doi.org/10.1039/C2PY20615C ). The colloidal particles position themselves at the oil-water interface hereby serving as Pickering stabilizers. Over time they deform and with the excess amount in the continuous water phase they form a non-covalently UPy-crosslinked hydrogel monolith. The reversible UPy crosslinks allow for the HIPE-hydrogels to be molded into objects which are thermo-responsive in Nature. You can read the paper here:  http://dx.doi.org/10.1039/C2CC38200H

In our 2013 Chemical Communications paper we report the fabrication of various shaped High Internal Phase Emulsion hydrogels. Key is the use of dilute waterborne poly(N-isopropylacrylamide) microgel dispersions which are non-covalently crosslinked through 2-ureido-4[1H] pyrimidinone (UPy) quadruple hydrogen bond groups. These microgels were developed in one of our earlier papers published in 2013 in Polymer Chemistry (read the paper here: http://dx.doi.org/10.1039/C2PY20615C). The colloidal particles position themselves at the oil-water interface hereby serving as Pickering stabilizers. Over time they deform and with the excess amount in the continuous water phase they form a non-covalently UPy-crosslinked hydrogel monolith. The reversible UPy crosslinks allow for the HIPE-hydrogels to be molded into objects which are thermo-responsive in Nature. You can read the paper here: http://dx.doi.org/10.1039/C2CC38200H