Soft Matter Composites: Design and Development

Particle-based Double Network Hydrogels

Double-network hydrogels are an extremely useful type of soft matter due to their high toughness and high water content. However, during their fabrication process they undergo significant swelling, making them difficult to utilize in composite applications or preventing their fabrication into complex shapes. By firstly preparing a sacrificial network out of gel particles, we can synthesize double-network hydrogels through a one-step process. This allows us to incorporate these types of gels into composites, as surface coatings, and as interfacial glues.

Publications:

  • Takahashi, R.; Shimano, K.; Okazaki, H.; Kurokawa, T.; Nakajima, T.; Nonoyama, T.; King, D. R.; Gong, J. P. “Tough Particle-Based Double Network Hydrogels for Functional Solid Surface Coatings” Advanced Materials Interfaces. 2018, 5 (23): 1801018.


Double-Network Hydrogels from Physical Sacrificial Networks

ダブルネットワークゲルの第一網目は、エネルギーを散逸させて亀裂の進展を防ぐ犠牲結合として機能することで、靭性を著しく向上させています。犠牲結合は一般的に、高分子網目が完全に伸びきった状態になるまで膨潤させることで形成されます。私たちは、網目鎖を伸長するためにこのような膨潤プロセスを利用するのではなく、硬い高分子電解質を柔らかい高分子網目に組み込み、多価金属イオンへ含侵・架橋することで、超分子犠牲網目を形成できることを発見しました。この手法は、よりシンプルな1ステップの重合プロセスであり、自己修復性を組み込むことも可能です。加えて、超分子網目の形成時に機械刺激を加えることで犠牲網目の配向を制御でき、配向に基づいた力学特性を有する異方性ハイドロゲルを作製することが出来ます。多くの生体材料は異方性を持っているため、この方法は人工生体材料の開発にも役立つと考えています。

Publications:

  • King, D. R.*,‡; Takahashi‡, R.; Ikai, T.‡; Fukao, K.; Kurokawa, T.; Gong, J. P.* “Anisotropic Double Network Hydrogels via Controlled Orientation of a Physical Sacrificial Network.” ACS Applied Polymer Materials. 2020, 2 (6): 2350-2358.

  • Takahashi, R.; Ikai, T.; Kurokawa, T.; King, D. R.*; Gong, J. P.* “Double Network Hydrogels Based on Semi-rigid Polyelectrolyte Physical Networks.” Journal of Materials Chemistry B. 2019, 7 (41), 6347–6354.

Fiber Reinforced Soft Composites

Fiber reinforced polymers are commonly used in industrial applications, such as the materials that make up modern airplanes. Developing fiber-reinforced soft composites is very difficult, because these types of composites generally fail either due to interfacial delamination, or by the fibers rupturing the soft matrix. We have determined that three requirements exist that enable the fabrication of fiber-reinforced soft composites with extremely high toughness: 1) The fibers must be extremely stiff, 2) the matrix must be very tough, and 3) the interphase between these two components must be strong. By following these design parameters, we have developed soft composites with toughness greater than steel.


Publications:

  • Cui, W.; King, D. R.; Huang, Y.; Chen, L.; Sun, T. L.; Guo, Y. Z.; Saruwatari, Y.; Hui, C.-Y.; Kurokawa, T.; Gong, J. P. “Fiber-reinforced Viscoelastomers Show Extraordinary Crack Resistance that Exceeds Metals.” Advanced Materials. 2020, 32 (31): 1907180.

  • Huang, Y.; King, D. R.; Cui, W.; Sun, T. L.; Guo, H.; Kurokawa, T.; Brown, H. R.; Hui, C.-Y.; Gong, J. P.* “Superior Fracture Resistance of Fiber Reinforced Polyampholyte Hydrogels Achieved by Extraordinarily Large Energy-Dissipative Process Zones.” Journal of Materials Chemistry A. 2019, 7 (22): 13431–13440.

  • Huang, Y.; King, D. R.; Sun, T. L.; Nonoyama, T.; Kurokawa, T.; Nakajima, T.; Gong, J. P. “Energy-Dissipative Matrices Enable Synergistic Toughening in Fiber Reinforced Soft Composites.” Advanced Functional Materials. 2017, 27 (9): 1605350.

  • King, D. R.; Sun, T. L.; Huang, Y.; Kurokawa, T.; Nonoyama, T.; Crosby, A. J.; Gong, J. P. “Extremely Tough Composites from Fabric Reinforced Polyampholyte Hydrogels.” Materials Horizons. 2015, 2: 584-591.


Macroscale Double Networks

Traditional double network gels consist of two interpenetrating polymer networks, where sacrificial bonds exist on the molecular scale. By understanding the essence of this design, we have developed macroscale double-network composite materials. In this system, the sacrificial bonds are provided by a fabricated network on the millimeter scale. During deformation, the macroscale sacrificial network fractures dissipating energy, and the bulk matrix prevents global failure and enables high stretch. Force transmission occurs due to topological interlocking between the two phases, due to the interpenetrating structure. Since preferential interfacial interactions are not required, any material can be used to form a sacrificial network, from biomaterials such as wood, to synthetic plastics, to metal.

Publications:

  • Okumura, T., Takahashi, R., Hagita, K., King, D.R.*, and Gong, J.P.* (2021). Improving the strength and toughness of macroscale double networks by exploiting Poisson's ratio mismatch. Scientific Reports. 11, 13280.

  • King, D. R.*,‡; Okumura, T.‡; Takahashi, R.; Kurokawa, T.; Gong, J. P. “Macroscale Double Networks: Design Criteria for Optimizing Strength and Toughness.” ACS Applied Materials & Interfaces. 2019, 11 (38): 35343-35353.

  • Takahashi, R.; Sun, T. L.; Saruwatari, Y.; Kurokawa, T.; King, D. R.*; Gong, J. P.* “Creating Stiff, Tough, and Functional Hydrogel Composites with Low-Melting-Point Alloys” Advanced Materials. 2018, 30 (16): 1706885.