Author
Da-Qing Wu
Bio: Da-Qing Wu is an academic researcher from Cornell University. The author has contributed to research in topics: Self-healing hydrogels & Lower critical solution temperature. The author has an hindex of 9, co-authored 16 publications receiving 857 citations.
Papers
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TL;DR: The release data suggested that an improved controlled release could be achieved by the IPN-PNIPAAm hydrogels without losing their intelligent properties.
434 citations
TL;DR: The data obtained clearly show that these new smart hybrid hydrogels were responsive to the external changes of temperature as well as pH, and the magnitude of smart and hydrogel properties were found to depend on the feed composition ratio of the two precursors.
212 citations
TL;DR: In this article, the effect of the level of crosslinking on the properties of poly(N-isopropylacrylamide) (PNIPAAm) hydrogels was investigated in terms of their lower critical solution temperature (LCST), interior morphology, equilibrium swelling, and deswelling and swelling kinetics.
Abstract: In this study, the effect of the level of crosslinking on the properties of poly(N-isopropylacrylamide) (PNIPAAm) hydrogels was investigated in terms of their lower critical solution temperature (LCST), interior morphology, equilibrium swelling, and deswelling and swelling kinetics. The thermal analysis showed that PNIPAAm hydrogels, having a wide range of crosslinking levels, exhibited almost the same LCSTs, and this was different from what the conventional theory would have predicted. Scanning electron micrographs revealed that the interior network structure of the PNIPAAm matrix became more porous with an increase in the level of crosslinking. This more porous matrix provided numerous water channels for water diffusion in or out of the matrix and, therefore, an improved response rate to the external temperature changes during the deswelling process and the swelling process.
79 citations
TL;DR: The dextran-allyl isocyanate/poly(N-iso-propylacrylamide) (Dex-AI/PNIPAAm) hydrogel was designed and prepared by copolymerization of the modifieddextran with N-isopropylacRYlamide(NIPAA) to be biodegradable and intelligent.
Abstract: The dextran-allyl isocyanate/poly(N-iso-propylacrylamide) (Dex-AI/PNIPAAm) hydrogel was designed and prepared by copolymerization of the modified dextran with N-isopropylacrylamide(NIPAAm). Thisnovel Dex-AI/PNIPAAm hydrogel is biodegradable and intelligent due to its biodegradable dextran linkage and thermosensitive PNIPAAm moiety. With an increase in dextran content, it exhibits the increased lower critical solution temperature (LCST) and decreased porous microstructure. Also, the thermosensitivity of this hydrogel is also controllable and adjustable depending on the different compositions.
41 citations
TL;DR: These Dex-AI/PNIPAAm hybrid networks show improved temperature-induced intelligent properties, such as the faster and controllable response dynamics, which may find promising applications in a wide variety of fields, including biomedical and bioengineering fields.
Abstract: A partially biodegradable and thermosensitive hybrid hydrogel network (DAN series) based on dextran-allylisocyanate (Dex-AI) and poly(N-isopropylacrylamide) (PNIPAAm) was synthesized via UV photocrosslinking. These hybrid hydrogels were characterized in terms of their chemical structure, thermal, mechanical, morphological and temperature-induced swelling properties. The effect of the composition ratio of Dex-AI to PNIPAAm on such properties were examined. The differential scanning calorimetry data show that this Dex-AI/PNIPAAm hybrid network has an increased lower critical solution temperature (LCST) and glass transition temperature (Tg) with an increase in the Dex-AI content. The interior morphology of these hybrid hydrogels revealed a decreased porous microstructure with an increase in the Dex-AI content in the hybrid network. Furthermore, if the Dex-AI composition became too high, a distinctive network structure with two different microporous structures appeared. The mechanical properties of these hybrid hydrogels also increased with an increase in the Dex-AI content. The temperature dependence of the swelling ratio, the deswelling kinetics as well as the reswelling kinetics was also characterized by gravimetric method. When comparing with a normal PNIPAAm hydrogel, these Dex-AI/PNIPAAm hybrid networks, due to the presence of Dex-AI moiety, also show improved temperature-induced intelligent properties, such as the faster and controllable response dynamics, which may find promising applications in a wide variety of fields, such as biomedical and bioengineering fields.
33 citations
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TL;DR: The scope of this paper is to review the aqueous polymer solutions that exhibit transition to gel upon temperature change and focuses mainly on hydrogels based on natural polymers as well as poly(ethylene glycol)-biodegradable polyester copolymers.
1,093 citations
TL;DR: In this article, the authors discuss various assembly techniques available for effectively incorporating the strong and flexible graphene-based components into polymer matrices by utilization of weak and strong interfacial interactions available in functionalized graphene sheets.
918 citations
TL;DR: A historical overview of the developments in hydrogel research from simple networks to smart materials is provided to overcome several challenges to overcome for clinical translation.
688 citations
TL;DR: Sonication provides a useful new tool with which to initiate rapid sol-gel transitions, such as for cell encapsulation, with high ionic strength and temperature and low pH responsible for increasing gelation kinetics.
572 citations
TL;DR: An overview of in situ gelling systems and their potential in biomedical applications, both photopolymerizable as well as self-assembling hydrogels, based on either chemical crosslinks or physical interactions will be addressed.
571 citations