Fabrication and characterization of microencapsulated n-octadecane with silk fibroin–silver nanoparticles shell for thermal regulation


Novel microencapsulated n-octadecane with natural silk fibroin (SF) shell attached with silver nanoparticles (AgNPs) on its surface was synthesized in oil-in-water emulsion via a self-assembly method. No additional reductant was used in the in situ preparation of AgNPs due to the inherent reduction property of tyrosine (Tyr) residues in SF. The microstructures and particle sizes of the resultant microcapsules were investigated by using a scanning electron microscope (SEM) and a laser scattering particle size distribution analyzer. The resulting microcapsules exhibited a regular spherical morphology with a 4–5 µm narrow diameter distribution range. And the AgNPs attached to the surface exhibited an even distribution. According to the analytical results of DSC, TGA, and infrared system, the SF-AgNPs microcapsule presents enhanced thermal stability and obvious thermal regulation properties. In addition, it was found that the SF-AgNP microcapsule also exhibited a good antibacterial activity against both Gram-positive bacteria (Staphylococcus aureus), and Gram-negative bacteria (Escherichia coli). The SF-AgNPs microcapsule synthesized in this study could be a potential candidate for thermal regulation and healthcare applications.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8


  1. 1.

    W. Chalco-Sandoval, M. Jose Fabra, A. Lopez-Rubio, and J.M. Lagaron: Electrospun heat management polymeric materials of interest in food refrigeration and packaging. J. Appl. Polym. Sci. 131, 40661 (2014).

    Article  Google Scholar 

  2. 2.

    W. Chalco-Sandoval, M. Jose Fabra, A. Lopez-Rubio, and J.M. Lagaron: Development of polystyrene-based films with temperature buffering capacity for smart food packaging. J. Food Eng. 164, 55 (2015).

    CAS  Article  Google Scholar 

  3. 3.

    N. Sarier and E. Onder: Organic phase change materials and their textile applications: An overview. Thermochim. Acta 540, 7 (2012).

    CAS  Article  Google Scholar 

  4. 4.

    T. Kousksou, A. Arid, A. Jamil, and Y. Zeraouli: Thermal behavior of building material containing microencapsulated PCM. Thermochim. Acta 550, 42 (2012).

    CAS  Article  Google Scholar 

  5. 5.

    L. Chen, L. Xu, H. Shang, and Z. Zhang: Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system. Energy Convers. Manage. 50, 723 (2009).

    CAS  Article  Google Scholar 

  6. 6.

    C.Y. Zhao and G.H. Zhang: Review on microencapsulated phase change materials (MEPCMs): Fabrication, characterization and applications. Renewable Sustainable Energy Rev. 15, 3813 (2011).

    CAS  Article  Google Scholar 

  7. 7.

    M. Palanikkumaran, K.K. Gupta, A.K. Agrawal, and M. Jassal: Highly stable hexamethylolmelamine microcapsules containing n-octadecane prepared by in situ encapsulation. J. Appl. Polym. Sci. 114, 2997 (2009).

    CAS  Article  Google Scholar 

  8. 8.

    Y. Ozonur, M. Mazman, H.O. Paksoy, and H. Evliya: Microencapsulation of coco fatty acid mixture for thermal energy storage with phase change material. Int. J. Energy Res. 30, 741 (2006).

    CAS  Article  Google Scholar 

  9. 9.

    Y. Baimark, M. Srisa-ard, and P. Srihanam: Morphology and thermal stability of silk fibroin/starch blended microparticles. Express Polym. Lett. 4, 781 (2010).

    CAS  Article  Google Scholar 

  10. 10.

    Y. Jin, Y. Zhang, Y. Hang, H. Shao, and X. Hu: A simple process for dry spinning of regenerated silk fibroin aqueous solution. J. Mater. Res. 28, 2897 (2013).

    CAS  Article  Google Scholar 

  11. 11.

    Z. Cao, X. Chen, J. Yao, L. Huang, and Z. Shao: The preparation of regenerated silk fibroin microspheres. Soft Matter 3, 910 (2007).

    CAS  Article  Google Scholar 

  12. 12.

    W. Wei, Y. Zhang, H. Shao, and X. Hu: Posttreatment of the dry-spun fibers obtained from regenerated silk fibroin aqueous solution in ethanol aqueous solution. J. Mater. Res. 26, 1100 (2011).

    CAS  Article  Google Scholar 

  13. 13.

    L. Koh, Y. Cheng, C. Teng, Y. Khin, X. Loh, S. Tee, M. Low, E. Ye, H. Yu, Y. Zhang, and M. Han: Structures, mechanical properties and applications of silk fibroin materials. Prog. Polym. Sci. 46, 86 (2015).

    CAS  Article  Google Scholar 

  14. 14.

    J. Xie, J.Y. Lee, D.I.C. Wang, and Y.P. Ting: Silver nanoplates: From biological to biomimetic synthesis. ACS Nano 1, 429 (2007).

    CAS  Article  Google Scholar 

  15. 15.

    T.M. Benn and P. Westerhoff: Nanoparticle silver released into water from commercially available sock fabrics (vol 42, pg 4133, 2008). Environ. Sci. Technol. 42, 7025 (2008).

    CAS  Article  Google Scholar 

  16. 16.

    J. Tian, K.K.Y. Wong, C. Ho, C. Lok, W. Yu, C. Che, J. Chiu, and P.K.H. Tam: Topical delivery of silver nanoparticles promotes wound healing. ChemMedChem 2, 129 (2007).

    CAS  Article  Google Scholar 

  17. 17.

    S. Zhang, Y. Tang, and B. Vlahovic: A review on preparation and applications of silver-containing nanofibers. Nanoscale Res. Lett. 11, 80 (2016).

    Article  Google Scholar 

  18. 18.

    M.V.D.Z. Park, A.M. Neigh, J.P. Vermeulen, L.J.J. de la Fonteyne, H.W. Verharen, J.J. Briede, H. van Loveren, and W.H. de Jong: The effect of particle size on the cytotoxicity, inflammation, developmental toxicity and genotoxicity of silver nanoparticles. Biomaterials 32, 9810 (2011).

    CAS  Article  Google Scholar 

  19. 19.

    X. Fei, M. Jia, X. Du, Y. Yang, R. Zhang, Z. Shao, X. Zhao, and X. Chen: Green synthesis of silk fibroin-silver nanoparticle composites with effective antibacterial and biofilm-disrupting properties. Biomacromolecules 14, 4483 (2013).

    CAS  Article  Google Scholar 

  20. 20.

    S. Calamak, E.A. Aksoy, N. Ertas, C. Erdogdu, M. Sagiroglu, and K. Ulubayram: Ag/silk fibroin nanofibers: Effect of fibroin morphology on Ag+ release and antibacterial activity. Eur. Polym. J. 67, 99 (2015).

    CAS  Article  Google Scholar 

  21. 21.

    Y. Tian, X. Jiang, X. Chen, Z. Shao, and W. Yang: Doxorubicin-loaded magnetic silk fibroin nanoparticles for targeted therapy of multidrug-resistant cancer. Adv. Mater. 26, 7393 (2014).

    CAS  Article  Google Scholar 

  22. 22.

    P.R. Selvakannan, A. Swami, D. Srisathiyanarayanan, P.S. Shirude, R. Pasricha, A.B. Mandale, and M. Sastry: Synthesis of aqueous Au core–Ag shell nanoparticles using tyrosine as a pH-dependent reducing agent and assembling phase-transferred silver nanoparticles at the air–water interface. Langmuir 20, 7825 (2004).

    CAS  Article  Google Scholar 

  23. 23.

    L. Cao, F. Tang, and G. Fang: Preparation and characteristics of microencapsulated palmitic acid with TiO2 shell as shape-stabilized thermal energy storage materials. Sol. Energy Mater. Sol. Cells 123, 183 (2014).

    CAS  Article  Google Scholar 

  24. 24.

    I. Taketani, S. Nakayama, S. Nagare, and M. Senna: The secondary structure control of silk fibroin thin films by post treatment. Appl. Surf. Sci. 244, 623 (2005).

    CAS  Article  Google Scholar 

  25. 25.

    L. Zhao, J. Luo, H. Wang, G. Song, and G. Tang: Self-assembly fabrication of microencapsulated n-octadecane with natural silk fibroin shell for thermal-regulating textiles. Appl. Therm. Eng. 99, 495 (2016).

    CAS  Article  Google Scholar 

  26. 26.

    X. Zhang, X. Wang, and D. Wu: Design and synthesis of multifunctional microencapsulated phase change materials with silver/silica double-layered shell for thermal energy storage, electrical conduction and antimicrobial effectiveness. Energy 111, 498 (2016).

    CAS  Article  Google Scholar 

  27. 27.

    L. Kvitek, A. Panacek, J. Soukupova, M. Kolar, R. Vecerova, R. Prucek, M. Holecova, and R. Zboril: Effect of surfactants and polymers on stability and antibacterial activity of silver nanoparticles (NPs). J. Phys. Chem. C 112, 5825 (2008).

    CAS  Article  Google Scholar 

  28. 28.

    X. Chen, Z. Shao, D.P. Knight, and F. Vollrath: Conformation transition kinetics of Bombyx mori silk protein. Proteins: Struct., Funct., Bioinf. 68, 223 (2007).

    CAS  Article  Google Scholar 

  29. 29.

    J. Luo, Y. Zhang, Y. Huang, H. Shao, and X. Hu: A bio-inspired microfluidic concentrator for regenerated silk fibroin solution. Sens. Actuators, B 162, 435 (2012).

    CAS  Article  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Baohua Li.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Li, Y., Zhao, L., Wang, H. et al. Fabrication and characterization of microencapsulated n-octadecane with silk fibroin–silver nanoparticles shell for thermal regulation. Journal of Materials Research 34, 2047–2056 (2019). https://doi.org/10.1557/jmr.2019.20

Download citation