Liquid Crystalline Hydrogels. 2. Effects of Water on the Structural Ordering

Kaneko, Tatsuo; Yamaoka, Kanji; Gong, Jian Ping; Osada, Yoshihito

doi:10.1021/ma0001281

Cited by 20 publications

(44 citation statements)

References 11 publications

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“…In our previous work, water-swollen LC hydrogels were synthesized by copolymerization of AA and an LC monomer 11-(4'-cyanobiphenyloxy)undecyl acrylate (11CBA) in dimethylformamide solution [63][64][65][66]. Th e states of poly(11CBA-co-AA) after being swollen in water depended on the monomer compositions and water content, displaying multiphase behavior ( Figure 5(a)) [64]. At room temperature, the copolymers dissolved in water when the molar fraction of 11CBA (F 11CBA ) was below 0.18.…”

Section: Liquid-crystalline Hydrogelsmentioning

confidence: 99%

Hydrogels with self-assembling ordered structures and their functions

Gong

2011

NPG Asia Mater

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Biomimetic and bioinspired materials are receiving increasing attention because of their robust functionality and potential applications as artifi cial tissue [1,2]. For natural materials, a high degree of sophistication is achieved through self-organization of the various components into ordered and hierarchical structures following a well-defi ned pattern [2][3][4]. Biological tissue possesses these ordered structures, endowing the living organisms with mechanical toughness and functionality, as exemplifi ed by tissues such as bone and cartilage. Th erefore, eff orts should be made to introduce ordered and hierarchical structure into soft, and also hard, synthetic materials. Among the strategies developed to date, self-assembly is a convenient and powerful method for producing ordered structures [5].Self-assembly, the spontaneous organization of discrete components into organized structures, is widespread in nature, such as in protein folding and hybridization of the DNA double helix [3][4][5][6]. Self-assembled structures usually incorporate additional functionalities. For example, phospholipids form a lipid bilayer arou nd the cell as a barrier to the diffusion of ions and proteins, and tropocollagens self-assemble into fi brils collagens that are closely packed in parallel arrays in the tendon, endowing it with excellent mechanical properties [3]. Inspired by nature, molecular self-assembly that is directed through weak, noncovalent interactions has received tremendous attention for the development of systems with ordered structures and resultant functions [1,2,6,7]. Th ese eff orts have resulted in various functional materials based on self-assembled structures including solutions, elastomers, gels and hard materials [1,2,[7][8][9].Gels as a functional system is an emerging fi eld in themselves, possessing a responsiveness to external stimuli such as stress, light, temperature, pH and ionic strength [10]. Gels with molecular assemblies can be produced in organic solvent (organogels) or aqueous solvent (hydrogels). In this review, we focus primarily on functional hydrogels with self-assembled structures. Functional organogels produced by molecular self-assembly have been covered in several excellent reviews [11][12][13][14].Hydrogels as a functional material have their own advantages over organogels. Th e aqueous medium makes hydrogels an ideal candidate for soft biotissue, mimicking its functions for applications such as scaff olds for cell culturing [15,16]. However, producing structured hydrogels is not easy because the ordered structure formation and water content (which introduces fl uctuation) work in opposite directions. Th e typical kinds of molecules capable of forming self-assembled structures in aqueous media are amphiphile, block-copolymer and liquid-crystalline (LC) molecules. Under certain conditions, the ordered structures formed by molecular self-assembly can be frozen in physically or chemically crosslinked hydrogels with additional functionalities, such as anisotropic optical and mechanica...

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Section: Liquid-crystalline Hydrogelsmentioning

confidence: 99%

Hydrogels with self-assembling ordered structures and their functions

Gong

2011

NPG Asia Mater

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“…Temperature. In order to investigate the thermal behavior of the poly(SA-co-AA) gels, we have measured differential scanning calorimetry (DSC) thermogram at a scanning ratio of 58C min 21 under nitrogen. DSC thermograms of the poly(SA-co-AA) gels showed the endothermic and exothermic peaks at 48 and 428C upon heating and cooling, respectively, which was con®rmed to be the reversible order±disorder transition together with the results of X-ray study.…”

Section: Hydrogels With the Crystalline Orderingmentioning

confidence: 99%

“…We have synthesized the water-swollen hydrogels containing a mesogenic side chains 11-(4 0 -cyanobiphenyloxy) undecyl group, and investigated the effects of monomer compositions, temperature [20], and water content [21] on the structure. It was found that these hydrogels showed the polymorphism by changing the composition of mesogenic component and swelling degree.…”

Section: Introductionmentioning

confidence: 99%

Hydrogels with the ordered structures

Miyazaki

Yamaoka

Kaneko

et al. 2000

Science and Technology of Advanced Materials

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“…There are just a few studies that have been reported on LCGs that function at ambient temperature and in aqueous media, as is warranted for application of biomaterials devices . Osada and co‐workers systematically worked on synthesis and characterization of amphiphilic copolymers containing acrylic acid and cholesterol mesogens with unique mesomorphic behavior . In another study, Finkelmann and co‐workers synthesized side‐chain LC hydrogels using oligoethyleneoxide with potential application in contact lenses .…”

Section: Introductionmentioning

confidence: 99%

“…There have been three main approaches to develop LCGs as Matsuoka et al discussed in their work . The first approach is crosslinking lyotropic LC's into hydrogel form; however, the produced networks do not demonstrate full LC structure or hydrogel‐like behavior when higher concentrations of LC mesogens are used . The second approach is to utilize LC organogels and convert them to LC hydrogels without destroying the LC structure, which can be challenging .…”

Section: Introductionmentioning

confidence: 99%

A hydrogel‐forming liquid crystalline elastomer exhibiting soft shape memory

Torbati

Mather

2015

J Polym Sci B Polym Phys

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Research in the field of liquid crystalline polymers has recently witnessed the introduction of liquid crystalline hydrogels. Here, we report the synthesis and characterization of a new liquid crystalline network featuring elastomeric softness, water‐swelling and shape memory characteristics. By comparing with a nonmesogenic network prepared using the same procedure, we reveal structure–property relationships of the liquid crystalline and crystalline polymer networks. Wide angle and small angle X‐ray scattering studies were used to examine the liquid crystalline ordering in both dry and hydrated states. Such ordering was found to be related to the observed shape memory and actuation (two‐way shape memory) properties and these phenomena are highlighted with demonstrations of shape change in response to heat and water stimuli. This study provides insight into the mechanisms affecting the shape evolution of water activated anisotropic liquid crystalline hydrogels and enables the future design of materials or devices for a variety of applications such as biomaterials interacting with body fluids in a hydrated state. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 38–52

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Liquid Crystalline Hydrogels. 2. Effects of Water on the Structural Ordering

Cited by 20 publications

References 11 publications

Hydrogels with self-assembling ordered structures and their functions

Hydrogels with self-assembling ordered structures and their functions

Hydrogels with the ordered structures

A hydrogel‐forming liquid crystalline elastomer exhibiting soft shape memory

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