Hydrogels with superior mechanical properties from the synergistic effect in hydrophobic–hydrophilic copolymers

Mredha, Md. Tariful Islam,Pathak, Suraj Kumar,Tran, Van Tron,Cui, Jiaxi,Jeon, Insu Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.362 No.-

<P><B>Abstract</B></P> <P>The mechanical properties (e.g., modulus and strength) of conventional tough hydrogels are considerably inferior to those required for practical load-bearing applications. However, developing hydrogels with a combination of superior mechanical properties such as stiffness, strength, and toughness is very challenging. Herein, we propose a new design strategy based on the synergistic effect of hydrophobic/hydrophilic components to fabricate novel hydrogels with superior mechanical properties. Both hydrophobic and hydrophilic monomers were integrated into copolymer hydrogels using a simple two-step fabrication process, which led to the formation of a randomly distributed interconnected 3D structure of hard-phase and soft-phase regions comprising hydrophobic-rich and hydrophilic-rich components, respectively. The 3D structure of hard-phase regions imparted exceptional stiffness and strength, whereas soft-phase regions provided sacrificial bonds to achieve stretchability and toughness. Different hydrophobic monomers with widely variable extents of hydrophobicity were used. The obtained results indicated that hydrogels based on benzene-containing hydrophobic monomers and exhibiting a higher-than-ambient glass transition temperature can show superior mechanical properties. Highly water-stable physical hydrogels with water contents of 50–60 wt% and exceptionally high Young’s modulus (150–280 MPa), tensile strength (7–17 MPa), and fracture energy (6680–7450 J/m<SUP>2</SUP>) were developed; these values are far superior to those of single-component hydrogels and tough hydrogels reported to date. This combination of superior properties, reported here for the first time, is expected to significantly broaden the application of hydrogels. The proposed strategy is quite general and offers further opportunities to develop diverse ultra-stiff, strong, and tough functional hydrogels using suitable monomer combinations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New strategy of producing hydrogels with superior mechanical properties is described. </LI> <LI> Hydrophobic/hydrophilic components create nanostructure for synergistic property. </LI> <LI> Hydrophobic–rich component imparts stiffness and strength. </LI> <LI> Hydrophilic–rich component imparts stretchability and toughness. </LI> <LI> The prepared hydrogels are very stable in pure water, seawater, and salt solutions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Eggshell Membrane-incorporated Cell Friendly Tough Hydrogels with Ultra-Adhesive Property

( Yonghyun Gwon ),( Sunho Park ),( Woochan Kim ),( Jangho Kim ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.2

Adhesive and tough hydrogels have received increased attention for their potential biomedical applications. However, traditional hydrogels have limited utility in tissue engineering because they tend to exhibit low biocompatibility, low adhesiveness, and poor mechanical properties. Herein, the use of the eggshell membrane (ESM) for developing tough, cell-friendly, and ultra-adhesive hydrogels is described. The ESM enhances the performance of the hydrogel network in three ways. First, its covalent cross-linking with the polyacrylamide and alginate chains strengthens the hydrogel network. Second, it provides functional groups, such as amine and carboxyl moieties, which are well known for enhancing the surface adhesion of biomaterials, thereby increasing the adhesiveness of the hydrogel. Third, it is a bioactive agent and improves cell adhesion and proliferation on the constructed scaffold. In conclusion, this study proposes the unique design of ESM-incorporated hydrogels with high toughness, cell-friendly, and ultra-adhesive properties for various biomedical engineering applications.

Eggshell Membrane-incorporated Cell Friendly Tough Hydrogels with Ultra-Adhesive Property

( Yonghyun Gwon ),( Sunho Park ),( Woochan Kim ),( Hyoseong Kim ),( Jangho Kim ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.1

Adhesive and tough hydrogels have received increased attention for their potential biomedical applications. However, traditional hydrogels have limited utility in tissue engineering because they tend to exhibit low biocompatibility, low adhesiveness, and poor mechanical properties. Herein, the use of the eggshell membrane (ESM) for developing tough, cell-friendly, and ultra-adhesive hydrogels is described. The ESM enhances the performance of the hydrogel network in three ways. First, its covalent cross-linking with the polyacrylamide and alginate chains strengthens the hydrogel network. Second, it provides functional groups, such as amine and carboxyl moieties, which are well known for enhancing the surface adhesion of biomaterials, thereby increasing the adhesiveness of the hydrogel. Third, it is a bioactive agent and improves cell adhesion and proliferation on the constructed scaffold. In conclusion, this study proposes the unique design of ESM-incorporated hydrogels with high toughness, cell-friendly, and ultra-adhesive properties for various biomedical engineering applications.

Effects of precursor composition and mode of crosslinking on mechanical properties of graphene oxide reinforced composite hydrogels

Jang, Jinhyeong,Hong, Jisu,Cha, Chaenyung Elsevier 2017 Journal of the mechanical behavior of biomedical m Vol.69 No.-

<P><B>Abstract</B></P> <P>Graphene oxide (GO) is increasingly investigated as a reinforcing nanofiller for various hydrogels for biomedical applications for its superior mechanical strength. However, the reinforcing mechanism of GO in different hydrogel conditions has not been extensively explored and elucidated to date. Herein, we systematically examine the effects of various types of precursor molecules (monomers vs. macromers) as well as mode of GO incorporation (physical vs. covalent) on the mechanical properties of resulting composite hydrogels. Two hydrogel types, (1) polyacrylamide hydrogels with varying concentrations of acrylamide monomers and (2) poly(ethylene glycol) (PEG) hydrogels with varying molecular weights of PEG macromers, are used as model systems. In addition, incorporation of GO is also controlled by using either unmodified GO or methacrylic GO (MGO) which allows for covalent incorporation. The results in this study demonstrate that the interaction between GO and the surrounding network and its effect on the mechanical properties (i.e. rigidity and toughness) of composite hydrogels are highly dependent on both the type and concentration of precursors and the mode of crosslinking. We expect this study will provide an important guideline for future research efforts on controlling the mechanical properties of GO-based composite hydrogels.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Flexible hydrogel-polymer electrolytes based on poly(vinyl alcohol) with high strength and toughness

최종선,김소연 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.1

Non-swellable, cytocompatible pHEMA-alginate hydrogels with high stiffness and toughness

Kim, Yong-Woo,Kim, Ji Eun,Jung, Youngmee,Sun, Jeong-Yun Elsevier 2019 Materials Science and Engineering C Vol.95 No.-

<P><B>Abstract</B></P> <P>Human skin exhibits high stiffness of up to 100 MPa and high toughness of up to 3600 J m<SUP>−2</SUP> despite its high water content of 40–70 wt%. Engineering hydrogels have rarely possessed both high stiffness and toughness, because compliant hydrogels usually become brittle when excess crosslinker is added to make the gel stiff. Furthermore, conventional hydrogels usually swell under physiological conditions, weakening their mechanical properties. Here, we designed a non-swellable hydrogel with high stiffness and toughness by interpenetrating covalently and ionically crosslinked networks. The stiffness is enhanced by utilizing ionic crosslinking sites fully, and the toughness is enhanced by adopting synergistic effects between energy-dissipation by ionic networks and crack-bridging by covalent networks. Non-swelling behaviors of the gel are achieved by densifying covalent and ionic crosslinks. The hybrid gel shows high elastic moduli (up to 108 MPa) and high fracture energies (up to 8850 J m<SUP>−2</SUP>). In vitro and in vivo swelling tests prove non-swelling behaviors of the gel. Live/dead assays show 99% cell viability over a period of 60 days.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Enhanced stiffness (~108 MPa) and toughness (~8,850 J m<SUP>-2</SUP>) of pHEMA-alginate hydrogels were comparable with those of human skin. </LI> <LI> Non-swelling behaviors of the gels were stable under in vivo conditions. </LI> <LI> 99% cell viability over a period of 60 days was shown via live/dead assays. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

하이드로젤 비드를 포함한 상호 침투 고분자 네트워크 하이드로젤 멤브레인의 제조 및 특성 분석

김도형,강문성 한국막학회 2019 멤브레인 Vol.29 No.4

In this study, alginate-based hydrogel membranes composed of hydrogel beads and highly tough hydrogel matrix including moisturizing oil and natural emulsifier were prepared and their elution characteristics were evaluated. As a result, it was confirmed that the elution rate of the moisturizing oil component can be controlled within a desired range by controlling the composition of the hydrogel bead and the tough hydrogel matrix. In particular, it has been confirmed that by combining tough hydrogel having a structure of interpenetrating polymer network (IPN) and hydrogel beads, the physical stability of the membranes can be improved and the elution rate of the moisturizing oil can also be controlled more finely. 본 연구에서는 보습오일 및 천연유화제를 포함한 하이드로젤 비드 및 고강도 하이드로젤 매트릭스로 구성된 알지네이트 기반의 하이드로젤 멤브레인을 제조하고 용출 특성을 평가하였다. 실험 결과, 하이드로젤 비드 및 고강도 하이드로젤의 조성을 조절하여 보습오일 성분의 용출 속도를 원하는 범위로 제어할 수 있음을 확인하였다. 특히 상호 침투 고분자 네트워크 구조를 가지고 있는 고강도 하이드로젤과 하이드로젤 비드를 결합함으로써 멤브레인의 물리적 안정성을 높이고 동시에보습오일의 용출 속도를 더욱 세밀하게 제어할 수 있음을 확인하였다.

Conjoined-network induced highly tough hydrogels by using copolymer and nano-cellulose for oilfield water plugging

Jintao Li,Peng Wei,Yahong Xie,Ziteng Liu,Hongjie Chen,Long He 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Hydrogels have been widely adopted for in-depth water control in mature oilfields, however, the poormechanical properties limit their application. Herein, a conjoined-network induced hydrogel was preparedthrough the in-situ free radical copolymerization of acrylamide (AM), Acrylic acid (AA) and N,N0-methylenebis(acrylamide) (MBA) in the presence of nano-cellulose (CNF/ACNF), and the coordinationeffect between aluminium ion and carboxyl. The results showed that a small amount of nano-cellulose(0.2 %) increased the compressive strength of the hydrogel by 7 times. The presence of nano-celluloseendowed the hydrogel with excellent thermal stability and high shearing elasticity, at the same time,could effectively reduced the swelling rate that hindered its disintegration in practical application. Theevaluation of sand-pack plugging suggested that the double cross-linked nano-cellulose hydrogel presenteda significant capacity for efficient water plugging, where the breakthrough pressure gradientwas as high as 23.73 MPa, the plugging rate reached 99.9%, and the maximum residual resistance factorwas 3902.06. This work provided a novel design of hydrogel with high compressive strength and satisfactorystability for water shutoff and conformance control in heterogeneous oil reservoirs.

Double network hydrogels with extremely high toughness and their applications

나양호 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.4

Polymer hydrogels attract attention as excellent soft and wet materials. However, common hydrogels are mechanically too soft and brittle to be used as load-bearing substances. By mimicking the structure of the articular cartilage, which is one of the native tough hydrogels, double network (DN) hydrogel with extremely high mechanical performance has been developed. Having high water content (about 90 wt%), DN gels consist of two types of polymer components with opposite physical natures: the minor component (the first network) abundantly cross-linked polyelectrolytes, and the major component (the second network) comprised of poorly cross-linked neutral polymers. Under suitable conditions, DN gels exhibit 0.1-1 MPa of elastic modulus, 20-60 MPa of compressive fracture stress, 1,000-2,000% of tensile strain, and 100-1,000 J m−2 of fracture energy. These excellent mechanical properties are comparable to those of rubber and natural bio-tissues. This paper reviews the main principle of DN gels, including their preparation method, mechanical feature, and toughening mechanism. The processability and the applicability of DN hydrogels as biomaterials and as conductive materials are also discussed.

Biocatalytic tough protein hydrogel for carbon sequestration

김창섭 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Development of carbonic anhydrase (CA)-based materials for environ-mentally- friendly sequestration carbon dioxide (CO₂) under mild conditions would be highly valuable for controlling emissions to the environment and for producing value-added chemicals. Here, a highly tough and stable CA-encapsulated silk protein hydrogel was developed for CO₂ sequestration through a bioinspired dual-crosslinking strategy that employed photo-induced dityrosine chemical crosslinking followed by dehydration-mediated physical crosslinking. The dualcrosslinked CA-encapsulated silk hydrogel facilitated the sequestration of CO₂ into calcium carbonate with high CO₂ hydration activity. The dual-crosslinked CA-encapsulated silk hydrogel exhibited a significant mechanical properties and structural stability. Thus, the unique combination of bioinspired dual-crosslinking with silk fibroin protein and CA enzyme demonstrates the successful application of protein hydrogel for CO₂ sequestration.