Development of bifunctional microencapsulated phase change materials with crystalline titanium dioxide shell for latent-heat storage and photocatalytic effectiveness

A sort of novel bifunctional microencapsulated phase change material (PCM) was designed by encapsulating n-eicosane into a crystalline titanium dioxide (TiO2) shell and, then, was successfully synthesized through in-situ polycondensation in the sol–gel process using tetrabutyl titanate as a titania precursor. The resultant microcapsule samples were characterized by Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to determine their chemical compositions and structures. Furthermore, the crystallinity of the TiO2 shell was verified by powder X-ray diffraction patterns. It was confirmed that the fluorinions could induce the phase transition from the amorphous TiO2 to the brookite-form crystals during the sol–gel process, thus resulting in a crystalline TiO2 shell for the microencapsulated n-eicosane. The scanning and transmission electron microscopy investigations indicated that all of the resultant microcapsules presented a perfect spherical shape with a uniform particle size of 1.5–2μm, and they also exhibited a well-defined core–shell structure as well as a smooth and compact shell. The crystalline TiO2 shell made the resultant microcapsules a photocatalytic activity, and therefore, these microcapsules demonstrated a good photocatalytic effect for the chemical degradation and an antimicrobial function for some of the Gram-negative bacteria. Most of all, all of the microencapsulated n-eicosane samples indicated good phase-change performance and high thermal reliability for latent-heat storage and release, and moreover, they achieved a high encapsulation efficiency and a high thermal-storage capability. The bifunctional microencapsulated n-eicosane synthesized in this study will be a potential candidate for the applications of waste heat recovery and treatment, intelligent textiles or fabrics for the warmth underwear and medical protective clothing, preservation and sterilization of foods, and solar energy storage and recovery, etc.

[1]  Xiaodong Wang,et al.  Design and synthesis of magnetic microcapsules based on n-eicosane core and Fe3O4/SiO2 hybrid shell for dual-functional phase change materials , 2014 .

[2]  J. Su,et al.  Fabrication and thermal properties of microPCMs: Used melamine‐formaldehyde resin as shell material , 2006 .

[3]  Mónica Delgado,et al.  Review on phase change material emulsions and microencapsulated phase change material slurries: Materials, heat transfer studies and applications , 2012 .

[4]  Huanzhi Zhang,et al.  Silica encapsulation of n-octadecane via sol-gel process: a novel microencapsulated phase-change material with enhanced thermal conductivity and performance. , 2010, Journal of colloid and interface science.

[5]  Pramod B. Salunkhe,et al.  A review on effect of phase change material encapsulation on the thermal performance of a system , 2012 .

[6]  S. Chuang,et al.  Probing Methylene Blue Photocatalytic Degradation by Adsorbed Ethanol with In Situ IR , 2007 .

[7]  E. Sirota,et al.  Rotator phases of the normal alkanes: An x‐ray scattering study , 1993 .

[8]  N. Sottos,et al.  In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene , 2003, Journal of microencapsulation.

[9]  Jun Hee Sung,et al.  Microcapsules containing electrophoretic suspension of TiO2 modified with poly(methyl methacrylate) , 2006 .

[10]  Z. Xiong,et al.  Rate Enhancement and Rate Inhibition of Phenol Degradation over Irradiated Anatase and Rutile TiO2 on the Addition of NaF: New Insight into the Mechanism , 2007 .

[11]  S. M. Sadrameli,et al.  A review of microencapsulation methods of phase change materials (PCMs) as a thermal energy storage (TES) medium , 2014 .

[12]  A. Sharma,et al.  Review on thermal energy storage with phase change materials and applications , 2009 .

[13]  Huanzhi Zhang,et al.  Fabrication of microencapsulated phase change materials based on n-octadecane core and silica shell through interfacial polycondensation , 2011 .

[14]  Xiaodong Wang,et al.  New approach for sol–gel synthesis of microencapsulated n-octadecane phase change material with silica wall using sodium silicate precursor , 2014 .

[15]  Serge Bourbigot,et al.  Microencapsulation of ammonium phosphate with a polyurethane shell part I: Coacervation technique , 2005 .

[16]  Mohammed M. Farid,et al.  A Review on Energy Conservation in Building Applications with Thermal Storage by Latent Heat Using Phase Change Materials , 2021, Thermal Energy Storage with Phase Change Materials.

[17]  Changying Zhao,et al.  Review on microencapsulated phase change materials (MEPCMs): Fabrication, characterization and applications , 2011 .

[18]  E. Sirota,et al.  PHASE TRANSITIONS AMONG THE ROTATOR PHASES OF THE NORMAL ALKANES , 1994 .

[19]  S. Ogale,et al.  Exploring anatase-TiO2 doped dilutely with transition metal ions as nano-catalyst for H2O2 decomposition: Spectroscopic and kinetic studies , 2013 .

[20]  Xiaodong Wang,et al.  Microencapsulation of n-octadecane phase change material with calcium carbonate shell for enhancement of thermal conductivity and serving durability: Synthesis, microstructure, and performance evaluation , 2014 .

[21]  Ying Zhao,et al.  Effect of geometrical confinement on the nucleation and crystallization behavior of n-alkane mixtures. , 2008, The journal of physical chemistry. B.

[22]  B. Vincent,et al.  Controlled release of 4-nitroanisole from poly(lactic acid) nanoparticles. , 2002, Journal of controlled release : official journal of the Controlled Release Society.

[23]  Min Xiao,et al.  Preparation and performance of shape stabilized phase change thermal storage materials with high thermal conductivity , 2002 .

[24]  Yucheng He,et al.  Synthesis and characterization of bioinspired hierarchical mesoporous TiO2 photocatalysts , 2013 .

[25]  Fangqiong Tang,et al.  General Synthesis and Optical Properties of Monodisperse Multifunctional Metal-Ion-Doped TiO2 Hollow Particles , 2009 .

[26]  Jinlong Zhang,et al.  Investigation of phase transitions for the hydrothermal formation of TiO2 in the presence of F− ions , 2013 .

[27]  S. Himran,et al.  Characterization of Alkanes and Paraffin Waxes for Application as Phase Change Energy Storage Medium , 1994 .

[28]  S. H. Choi,et al.  Thermal characteristics of paraffin in a spherical capsule during freezing and melting processes , 2000 .

[29]  Po Keung Wong,et al.  Photocatalytic activity, antibacterial effect, and photoinduced hydrophilicity of TiO2 films coated on a stainless steel substrate. , 2003, Environmental science & technology.

[30]  L.-Y. Wang,et al.  Preparation of silica microspheres encapsulating phase-change material by sol-gel method in O/W emulsion , 2006, Journal of microencapsulation.

[31]  Yulong Ding,et al.  A one-step method for producing microencapsulated phase change materials , 2010 .

[32]  A. Sari,et al.  Preparation, characterization and thermal properties of PMMA/n-heptadecane microcapsules as novel solid-liquid microPCM for thermal energy storage , 2010 .

[33]  Bao Yang,et al.  Supercooling suppression of microencapsulated phase change materials by optimizing shell composition and structure , 2014 .

[34]  Dan Zhou,et al.  Review on thermal energy storage with phase change materials (PCMs) in building applications , 2012 .

[35]  J. Herrmann,et al.  Photocatalytic degradation pathway of methylene blue in water , 2001 .

[36]  Luisa F. Cabeza,et al.  Materials used as PCM in thermal energy storage in buildings: A review , 2011 .

[37]  Jinlong Zhang,et al.  Preparation of controllable crystalline titania and study on the photocatalytic properties. , 2005, The journal of physical chemistry. B.

[38]  Xiaodong Wang,et al.  Self-Assembly Synthesis of Microencapsulated n-Eicosane Phase-Change Materials with Crystalline-Phase-Controllable Calcium Carbonate Shell , 2014 .

[39]  Lin Pan,et al.  Preparation, characterization and thermal properties of micro-encapsulated phase change materials , 2012 .

[40]  P. Vary,et al.  Anatase TiO2 nanocomposites for antimicrobial coatings. , 2005, The journal of physical chemistry. B.

[41]  Zhong Chen,et al.  Enhanced Photocatalytic Hydrogen Production with Synergistic Two-Phase Anatase/Brookite TiO2 Nanostructures , 2013 .

[42]  G. Fang,et al.  Preparation and characteristics of microencapsulated palmitic acid with TiO2 shell as shape-stabilized thermal energy storage materials , 2014 .

[43]  Benxia Li,et al.  Fabrication and Properties of Microencapsulated Paraffin@SiO2 Phase Change Composite for Thermal Energy Storage , 2013 .

[44]  Hui Chen,et al.  Preparation of phase change materials microcapsules by using PMMA network‐silica hybrid shell via sol‐gel process , 2009 .

[45]  S. Khoee,et al.  New Approach for the Elucidation of PCM Nanocapsules through Miniemulsion Polymerization with an Acrylic Shell , 2011 .

[46]  Xiaodong Wang,et al.  Synthesis and properties of microencapsulated n-octadecane with polyurea shells containing different soft segments for heat energy storage and thermal regulation , 2009 .

[47]  N. Sottos,et al.  In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene , 2003 .

[48]  A. Sari,et al.  Fatty acid/poly(methyl methacrylate) (PMMA) blends as form-stable phase change materials for latent heat thermal energy storage , 2008 .