单域液晶的弹性体和液晶橡胶纳米复合材料的制备
Summary
We demonstrate the preparation of siloxane-based and epoxy-based liquid crystal elastomers (LCEs) and LCE nanocomposites. The LCEs are characterized with respect to reversible strain, liquid crystal ordering, and stiffness. As a potential application, we demonstrate their use as shape-responsive substrates in a custom device for active cell culture.
Abstract
LCES是形状响应材料具有完全可逆的形状变化和在医学应用潜力，组织工程，人工肌肉，并作为软机器人。这里，我们证明形状响应液晶弹性体（LCES）和LCE纳米复合材料的制备其形状的响应的表征，机械性能，和显微组织沿。两种类型LCES的 – 聚硅氧烷 – 基和环氧基 – 合成，对齐，和特征。基于聚硅氧烷的LCES通过两个交联步骤中，所施加的负载下的第二次制备，产生单畴LCES。聚硅氧烷LCE纳米复合材料是通过加入导电性炭黑纳米粒子的制备，无论是在整个批量的LCE的并向LCE表面。基于环氧LCES通过可逆酯化反应制备。基于环氧LCES通过一个单轴负载在升高（160℃）t时应用对准emperatures。对准LCES和LCE纳米复合材料使用的成像，二维X射线衍射测量，差示扫描量热法，和动态力学分析的组合，其特征相对于可逆应变，机械刚度，以及液晶排序。 LCES和LCE纳米复合材料可以用热和/或电势被刺激可控产生在细胞培养基的菌株，我们证明LCES的应用作为使用定做装置用于细胞培养的形状响应衬底。
Introduction
可以表现出快速的，可逆的，可编程的形状改变的材料是可取的一些新兴的应用1-9。形状响应支架可以帮助伤口愈合，治疗7。人工机器人可以在勘探或在有害或不安全的人类10环境中执行任务的帮助。形状响应弹性体是所希望的用于在活性细胞培养物，其中细胞在活性环境中培养的用11-14其它应用包括包装，传感，和药物递送。
液晶弹性体（LCE）与液晶订货15-20的聚合物网络。 LCES通过柔性聚合物网络与被称为介晶液晶分子相结合进行。 LCES的响应是从液晶秩序的偶合而得到影响介晶的排序的聚合物网络中的菌株，并刺激将基因率网的菌株，反之亦然。为了实现在没有外部负载的大的和可逆的形状变化，介晶必须在LCE单个方向对准。在LCES工作的一个常见实用的挑战是产生单畴LCES。另一个挑战是产生形状的变化响应于刺激其他比直接加热。这可以通过增加纳米颗粒或染料来LCE网络21-28来完成。
这里，我们证明单畴LCES和LCE纳米复合材料的制备。首先，我们证明了使用两步法首先由枯否等报道单畴LCES 的制备。29，这仍然是一种制备单畴LCES，但实现取向均匀性和一致性的样品之间是具有挑战性的最流行 的和公知的方法。我们证明可以使用标准的实验室设备很容易实现的方法，包括抽样的全部细节处理和准备。下一步，我们表明导电炭黑纳米颗粒如何可以被添加到LCES以产生导电性，电响应LCES。然后我们证明环氧基LCES的合成和对准。这些材料表现出可交换网络键，并且可以通过加热到高温，并施加均匀的载荷对齐。所有LCES通过宏观样品成像，X射线衍射测量和动态力学分析表征。最后，我们证明LCES为活跃细胞培养形状响应衬底中的一个潜在的应用。
Protocol
Representative Results
Discussion
In order to produce monodomain LCEs, the LCEs need to be uniaxially loaded during crosslinking. This is challenging in practice because the LCE is loaded when it is only partially crosslinked, and therefore is not mechanically robust and can easily break or tear. The procedure described above (steps 1.1 – 1.4) can produce monodomain LCEs consistently. One critical step is the removal of the LCE from the PTFE mold for loading at the appropriate time. If the LCE is removed too quickly, it will easily break or tear. On the…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项工作是由美国国家职业基金会（CBET-1336073至RV），ACS的石油研究基金（52345-DN17至RV），美国心脏协会（BGIA到JGJ），美国国家科学基金会（CAREER支持CBET-1055942至JGJ），健康/美国国家心脏，肺和血液研究所（1R21HL110330到JGJ），路易斯和桃子欧文和得克萨斯儿童医院的国家机构。
Materials
| 4-methoxyphenyl 4-(3-butenyloxy)benzoate | TCI America | M2106 | Reactive mesogen |
| poly(methylhydrosiloxane) | Gelest | HMS-993 | Reactive polysiloxane |
| 1,4-di(10-undecenyloxybenzene) | N/A | N/A | see: Ali, S. A., Al-Muallem, H. A., Rahman, S. U. & Saeed, M. T. Bis-isoxazolidines: A new class of corrosion inhibitors of mild steel in acidic media. Corrosion Science 50 (11), 3070–3077, doi:10.1016/j.corsci.2008.08.011 (2008) |
| (dichloro(1,5-cyclooctadiene)-platinum(II) | Sigma Aldrich | 244937 | Pt catalyst |
| PTFE mold | N/A | N/A | fabricated at Rice machine shop |
| carbon black nanoparticles | Cabot | VULCAN® XC72R | used in the synthesis of LCE nanocomposites |
| polystyrene | Sigma Aldrich | 331651 | linear polystyrene |
| 4,4'-diglycidyloxybiphenyl | N/A | N/A | see: Giamberjni, M., Amendola, E. & Carfagna, C. Liquid Crystalline Epoxy Thermosets. Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 266 (1), 9–22, doi:10.1080/10587259508033628 (1995). |
| sebacic acid | Sigma Aldrich | 283258 | C8 linking group for epoxy-LCE synthesis |
| hexadecanedioic acid | Sigma Aldrich | 177504 | C16 linking group for epoxy-LCE synthesis |
| carboxydecyl-terminated polydimethylsiloxane | Gelest | DMS-B12 | Siloxane linking group for epoxy-LCE synthesis |
| 1,5,7-triazabicyclo[4.4.0] dec-5-ene | Sigma Aldrich | 345571 | catalyst for reversible LCEs |
| carbon rods | Ladd Research | 30250 | used in cell culture experiments |
| medical grade silicone adhesive | Silbione | MED ADH 4100 RTV | used to adhere carbon rods to vessel |
References
- Nikkhah, M., Edalat, F., Manoucheri, S., Khademhosseini, A. Engineering microscale topographies to control the cell-substrate interface. Biomaterials. 33 (21), 5230-5246 (2012).
- Mather, P. T., Luo, X., Rousseau, I. A. Shape Memory Polymer Research. Annu. Rev. Mater. Res. 39 (1), 445-471 (2009).
- Small, W., Singhal, P., Wilson, T. S., Maitland, D. J. Biomedical applications of thermally activated shape memory polymers. J. Mater. Chem. 20 (17), 3356-3366 (2010).
- Rickert, D., Lendlein, A., Peters, I., Moses, M. A., Franke, R. P. Biocompatibility testing of novel multifunctional polymeric biomaterials for tissue engineering applications in head and neck surgery: an overview. Eur. Arch. Oto-Rhino-Laryngol. Head Neck. 263 (3), 215-222 (2006).
- Chen, Q., Liang, S., Thouas, G. A. Elastomeric biomaterials for tissue engineering. Prog. Polym. Sci. 38 (3-4), 584-671 (2013).
- Mano, J. F. Stimuli-Responsive Polymeric Systems for Biomedical Applications. Adv. Eng. Mater. 10 (6), 515-527 (2008).
- Ratna, D., Karger-Kocsis, J. Recent advances in shape memory polymers and composites: a review. J. Mater. Sci. 43 (1), 254-269 (2008).
- Biggs, J., Danielmeier, K., et al. Electroactive Polymers: Developments of and Perspectives for Dielectric Elastomers. Angew. Chem. Int. Ed. 52 (36), 9409-9421 (2013).
- Ware, T. H., McConney, M. E., Wie, J. J., Tondiglia, V. P., White, T. J. Voxelated liquid crystal elastomers. Science. 347 (6225), 982-984 (2015).
- Shepherd, R. F., Ilievski, F., et al. Multigait soft robot. Proc. Natl. Acad. Sci. 108 (51), 20400-20403 (2011).
- Agrawal, A., Adetiba, O., Kim, H., Chen, H., Jacot, J. G., Verduzco, R. Stimuli-responsive liquid crystal elastomers for dynamic cell culture. J. Mater. Res. 30 (04), 453-462 (2015).
- Yang, P., Baker, R. M., Henderson, J. H., Mather, P. T. In vitro wrinkle formation via shape memory dynamically aligns adherent cells. Soft Matter. 9 (18), 4705-4714 (2013).
- Xu, X., Davis, K. A., Yang, P., Gu, X., Henderson, J. H., Mather, P. T. Shape Memory RGD-Containing Networks: Synthesis, Characterization, and Application in Cell Culture. Macromol. Symp. 309-310 (1), 162-172 (2011).
- Davis, K. A., Luo, X., Mather, P. T., Henderson, J. H. Shape Memory Polymers for Active Cell Culture. J Vis Exp. , e2903 (2011).
- Warner, M., Terentjev, E. M. . Liquid Crystal Elastomers. , (2003).
- Urayama, K. Selected Issues in Liquid Crystal Elastomers and Gels. Macromolecules. 40 (7), 2277-2288 (2007).
- Fleischmann, E. K., Zentel, R. Liquid-Crystalline Ordering as a Concept in Materials Science: From Semiconductors to Stimuli-Responsive Devices. Angew. Chem. Int. Ed. 52 (34), 8810-8827 (2013).
- Ohm, C., Brehmer, M., Zentel, R. Liquid Crystalline Elastomers as Actuators and Sensors. Adv. Mater. 22 (31), 3366-3387 (2010).
- Jiang, H., Li, C., Huang, X. Actuators based on liquid crystalline elastomer materials. Nanoscale. 5 (12), 5225-5240 (2013).
- Burke, K. A., Rousseau, I. A., Mather, P. T. Reversible actuation in main-chain liquid crystalline elastomers with varying crosslink densities. Polymer. 55 (23), 5897-5907 (2014).
- Chambers, M., Finkelmann, H., Remškar, M., Sánchez-Ferrer, A., Zalar, B., Žumer, S. Liquid crystal elastomer-nanoparticle systems for actuation. J. Mater. Chem. 19 (11), 1524-1531 (2009).
- Chambers, M., Zalar, B., Remskar, M., Zumer, S., Finkelmann, H. Actuation of liquid crystal elastomers reprocessed with carbon nanoparticles. Appl. Phys. Lett. 89 (24), 243116 (2006).
- Kohlmeyer, R. R., Chen, J. Wavelength-Selective IR Light-Driven Hinges Based on Liquid Crystalline Elastomer Composites. Angew. Chem. Int. Ed. 52 (35), 9234-9237 (2013).
- Liu, X., Wei, R., Hoang, P. T., Wang, X., Liu, T., Keller, P. Reversible and Rapid Laser Actuation of Liquid Crystalline Elastomer Micropillars with Inclusion of Gold Nanoparticles. Adv. Funct. Mater. 25 (20), 3022-3032 (2015).
- Marshall, J. E., Terentjev, E. M. Photo-sensitivity of dye-doped liquid crystal elastomers. Soft Matter. 9 (35), 8547-8551 (2013).
- Marshall, J. E., Ji, Y., Torras, N., Zinoviev, K., Terentjev, E. M. Carbon-nanotube sensitized nematic elastomer composites for IR-visible photo-actuation. Soft Matter. 8 (5), 1570-1574 (2012).
- Camargo, C. J., Campanella, H., et al. Localised Actuation in Composites Containing Carbon Nanotubes and Liquid Crystalline Elastomers. Macromol. Rapid Commun. 32, 1953-1959 (2011).
- Ahir, S. V., Squires, A. M., Tajbakhsh, A. R., Terentjev, E. M. Infrared actuation in aligned polymer-nanotube composites. Phys Rev B. 73 (8), 085420 (2006).
- Küpfer, J., Finkelmann, H. Nematic liquid single crystal elastomers. Macromol Chem Rapid Commun. 12 (12), 717-726 (1991).
- Ali, S. A., Al-Muallem, H. A., Rahman, S. U., Saeed, M. T. Bis-isoxazolidines: A new class of corrosion inhibitors of mild steel in acidic media. Corros. Sci. 50 (11), 3070-3077 (2008).
- Giamberjni, M., Amendola, E., Carfagna, C. Liquid Crystalline Epoxy Thermosets. Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. Mol. Cryst. Liq. Cryst. 266 (1), 9-22 (1995).
- Agrawal, A., Luchette, P., Palffy-Muhoray, P., Biswal, S. L., Chapman, W. G., Verduzco, R. Surface wrinkling in liquid crystal elastomers. Soft Matter. 8 (27), 7138-7142 (2012).
- Agrawal, A., Chipara, A. C., et al. Dynamic self-stiffening in liquid crystal elastomers. Nat Commun. 4, 1739 (2013).
- Sharma, A., Neshat, A., et al. Biodegradable and Porous Liquid Crystal Elastomer Scaffolds for Spatial Cell Cultures. Macromol. Biosci. 15 (2), 200-214 (2015).
- Yeh, L. C., Dai, C. F., et al. Neat poly(ortho-methoxyaniline) electrospun nanofibers for neural stem cell differentiation. J. Mater. Chem. B. 1, 5469-5477 (2013).
- Krause, S., Dersch, R., Wendorff, J. H., Finkelmann, H. Photocrosslinkable Liquid Crystal Main-Chain Polymers: Thin Films and Electrospinning. Macromol. Rapid Commun. 28 (21), 2062-2068 (2007).
- Liu, D., Broer, D. J. Light controlled friction at a liquid crystal polymer coating with switchable patterning. Soft Matter. 10 (40), 7952-7958 (2014).
