Nanocomposite materials have been made for modulating the reflection of incident infrared light and regulating temperature, by depositing thin conductive layers of aluminum (10-100 nm) with the physical method of vaporizing metal atoms with a laser on polystyrene-ethylene-butylene-polystyrene elastomer films with thickness <100 microns, surface ~100 cm^2 and density <1 g/cm^3. The optimization of the manufacturing method of the nanocomposite samples was achieved, leading to: - a decrease in the heat flux transmitted in the non-actuated state (better reflective quality of the film), - an increase in the thermoregulatory capacity (increase in the modulated heat flux). Five sleeve prototypes were fabricated without the use of adhesives by hot calendering the optimized nanocomposite material with elastic and breathable textiles. A mathematical model was developed to estimate the temperature of the environment at which an individual feels comfortable while maintaining a constant skin temperature, with values ranging from 14.0 – 18.1 ℃, a temperature range similar to manufactured clothing from classic textile materials. The estimated cost price is between 7.6 - 8.8 Euro/piece, competitive on the fashion market. Garments have been made based on integrated thermoregulatory materials that modulate a heat flow of 21.3 W/m^2 with a temperature regulation capacity of 40 W/m^2 and very good breathability (15000 g/m^2/day ), through the dynamic change with uniaxial mechanical actuation of the reflection of the incident infrared light.
Results on first stage (2020)
During this stage, were manufactured nanocomposites with adaptive infrared (IR) reflectivity and thermoregulation by depositing thin conductive layers of aluminum or zinc oxide doped with aluminum on polymeric support or on textile material derived from commercial polymers. The deposition of the reflective thin layers (~ 100 nm) in IR was done by the physical method of pulsed laser ablation, PLD (Pulsed Laser Deposition). For the manufacture of 10 nanocomposite materials with adaptive infrared (IR) and thermoregulatory capacities, elastomeric or flexible polymers obtained by various polymerization reactions were used as growth support of the conductive film, as follows: styrene elastomers, ethylene-vinyl acetate, silicones by ring-opening polymerization followed by crosslinking with condensation, hydrosilylation or thiolene addition, and polysulfone. Using film-forming polymer casting techniques, such as doctor blading method, polymer films with a thickness of less than 100 micrometers, an area of approximately 100 cm^2 and a density were obtained. up to 1 g/cm^3. Also, 10 other composite materials with adaptive capacity in IR and thermoregulation were manufactured by using Al growth film on textile materials derived from commercial polymers such as polyester, polyester mixed with elastane or spandex, polypropylene, and cellulose. The best performance in terms of tests of adaptive infrared and thermoregulatory capacity were obtained for nanocomposite materials made on the basis of block linear copolymers polystyrene-ethylene-butylene-polystyrene, with thermoregulation of 21 W/m^2 for a mechanical performance up to at 50%.
Results on second stage (2021)
By performing a step of optimizing the manufacturing method of nanocomposite materials, the thermoregulatory performances were improved both in terms of increasing the thermoregulatory capacity at maximum mechanical actuation of 50%, as well as increasing the sensitivity of these composites manifested for relatively low values of mechanical actuation (up to 20%). This consisted in the selection of the best materials as support to grow the reflective film in IR (polymer or textile) and the optimization of the properties of deposition by PLD of the thin layer of Al or its replacement with a transparent and conductive film of ZnO doped with Al. Nanocomposite materials resulting from the deposition of thin reflective layers in IR were characterized in terms of thermoregulatory capacity, total heat flux transmitted, mechanical properties (Young's mode, elongation at break), interaction with water vapor by dynamic absorption of water vapor, chemical composition by gel permeability chromatography and structural X-ray diffraction for the verification of crystallinity changes induced by deposition of the reflective metal nanometric layer in IR. Thus, a nanocomposite material with a thermoregulatory capacity of 40 W/m2 was obtained. Finally, samples of thermoregulatory textile material were manufactured by hot calendering (without the addition of adhesives) of the optimized nanocomposite material with elastic and breathable textile fabric materials. The results of fundamental interest obtained during this project can be found in two published articles and one under evaluation, and in eleven presentations at conferences. Issues related to the optimal formulation of thermoregulatory material and the ability to provide thermal comfort to users are the subject of dissemination materials under development.
Results on third stage (2022)
In this step, were fabricated integrated thermoregulatory materials with the ability to manage heat flow by dynamically changing the infrared (IR) reflectivity through mechanical actuation and thermoregulation. The materials were produced by depositon of thin conductive layers of aluminum (<100 nm) on patterned polymer support from commercial polymers, followed by hot calendering with breathable elastic textile fabric. The realization of a nanoscale patterned polymer support allows the modulation of a higher heat flux in the form of IR radiation (21.3 W/m^2) and, respectively, a very good breathability of the material (~7500 g/m^2/day). The deposition of thin layers of aluminum (Al) (<100 nm) reflective in IR was achieved by the physical method of glancing angle pulsed laser ablation, PLD (Pulsed Laser Deposition). Ten samples of integrated thermoregulating material were manufactured using a polymer with high water vapor transport capacity, with samples’ thickness <200 microns and density <1 g/cm^3. The resulting materials were characterized from the point of view of thermoregulation capacity, total transmitted heat flow, mechanical properties, interaction with water vapor. The infrared thermoregulation capability testing was 5.5 W/m^2 and total heat flux of 40 W/m^2 for a mechanical performance of up to 30% for a material with block copolymer elastomeric matrix patterned, calendered with a textile material.
By optimizing the laboratory manufacturing procedure of the integrated thermoregulatory materials, the thermoregulatory performances obtained were improved in terms of increasing the thermoregulatory capacity for a maximum mechanical actuation of 50%, as well as the breathability of these materials (~15000 g/m^2/day). This consisted in optimizing the angled PLD deposition properties of the Al thin layer and improving the calendering parameters of the composite material patterned together with the textile material. Thus, an optimized thermoregulatory material was obtained with a total flux of >40 W/m^2 and thermoregulatory capacity of >21 W/m^2. Thermoregulatory material samples were used in the production of clothing garments and the thermal properties were measured with an infrared video camera.
The results obtained during the project can be found in four published articles, as well as in three presentations at international conferences in 2022 (and a total of fifteen presentations at international events throughout the durations of the project).
Scientific papers:
- Alina Soroceanu, George T. Stiubianu, Siloxane Matrix MolecularWeight Influences the Properties of Nanocomposites Based on Metal Complexes and Dielectric Elastomer, Materials 2021, 14, 3352. https://doi.org/10.3390/ma14123352 (articol open access).
- George Stiubianu, Cristian Ursu, Codrin Tugui, Adrian Bele, Alexandra Bargan, Mihaela Dascalu, Carmen Racles, Maria Cazacu, Aurelian Ciobotaru, Energy-Efficient Dynamic Polymer-Based Nanocomposites For Thermal Comfort, International Conference Progress in Organic and Macromolecular Compounds Proceedings (Online,
https://icmpp.ro/macroiasi2021/proceedings.php) 2021, ISSN 2810 – 2347 ISSN – L 2810 – 2126.
- Carmen Racles, Adrian Bele, Ana-Lavinia Vasiliu, Liviu Sacarescu, Emulsion Gels as Precursors for Porous Silicones and All-Polymer Composites – A Proof of Concept Based on Siloxane Stabilizers, Gels 2022, 8, 377. https://doi.org/10.3390/gels8060377
- Mihaela Dascalu, Alexandru‑Constantin Stoica, Adrian Bele, Ana‑Maria Macsim, Alexandra Bargan, Cristian‑Dragos Varganici, George‑Theodor Stiubianu, Carmen Racles, Sergiu Shova, Maria Cazacu, Octakis(Carboxyalkyl‑Thioethyl)Silsesquioxanes and Derived Metal Complexes: Synthesis, Characterization and Catalytic Activity Assessments, J. Inorg. Organomet. Polym. 2022. https://doi.org/10.1007/s10904-022-02408-8
- Daniela Filip, Doina Macocinschi, Mirela-Fernanda Zaltariov, Carmen Anatolia Gafitanu, Cristina Gabriela Tuchilus, Adrian Bele, Bianca-Iulia Ciubotaru, Elena Stoleru, Alexandra Bargan, Mucoadhesive and Antimicrobial Allantoin/β Cyclodextrins-Loaded Carbopol Gels as Scaffolds for Regenerative Medicine, Gels 2022, 8, 416. https://doi.org/10.3390/gels8070416
- Bianca-Iulia Ciubotaru, Mihaela Dascalu, Mirela-Fernanda Zaltariov, Ana-Maria Macsim, Madalin Damoc, Adrian Bele, Codrin Tugui, Cristian-Dragos Varganici, Maria Cazacu, Catalyst-free crosslinked sustainable functional silicones by supramolecular interactions, Soft Matter 2022.
Participations at international conferences:
1. A XXXI-a Editie a Congresului International “Pregatim Viitorul Promovand Excelenta”, Iasi, Univ. Apollonia, 2 Martie 2021 (conferinta online), Bioinspired materials for dynamic thermal comfort and all weather homeostasis, George Stiubianu, Carmen Racles, Mihaela Dascalu, Alexandra Bargan, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://www.univapollonia.ro/congres_2021_program_pe_sectiuni/
2. #RCS Twitter Conference 2021, 2-3 martie 2021 (conferinta online), Bioinspired Elastomer Materials for Dynamic Control of Infrared Energy Flux, George Stiubianu, #RSCPoster Twitter conference
3. Applied Nanotechnology and Nanoscience International Conference, Montrouge, France, ANNIC2021, 24-26 martie 2021 (conferinta online), Bioinspired Polymer Nanocomposites Providing Scalable Solution for Thermal Management, George Stiubianu, Carmen Racles, Mihaela Dascalu, Alexandra Bargan, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://premc.org/conferences/annic-nanotechnology-nanoscience/registration/#menu
4. ECRES2021, 9TH European Conference on Renewable Energy Systems, Istanbul, Turkey, 21-23 aprilie 2021 (conferinta online), Bioinspired Polymer Materials For Heating And Cooling Thermal Management Of Buildings, George Stiubianu, Alexandra Bargan, Mihaela Dascalu, Carmen Racles, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://www.ecres.net/registration.html
5. EuroNanoForum2021, 5-6 mai 2021 (conferinta online), Conformable Polymer Films Provide Thermal Comfort with Passive Heating and Cooling in Clothing and Buildings, George Stiubianu, Adrian Bele, Cristian Ursu, Mihaela Dascalu, Alexandra Bargan, Codrin Tugui, Carmen Racles, Maria Cazacu, https://euronanoforum2021.eu/
6. International Conferences and Exhibition on Nanotechnologies, Organic Electronics & Nanomedicine NANOTEXNOLOGY2021, Thessaloniki, Greece, 3-10 iulie 2021 (conferinta format mixt), Self-Actuated Thermal Comfort Clothing with Dielectric Elastomers, George Stiubianu, Codrin Tugui, Adrian Bele, Mihaela Dascalu, Alexandra Bargan, Cristian Ursu, Carmen Racles, Maria Cazacu, https://www.nanotexnology.com/index.php/call-for-abstracts-home
7. 15th International Conference on Materials Chemistry, Dublin, Ireland, 12-15 iulie 2021 (conferinta online), Bioinspired Nanocomposite Films for Human Comfort Thermal Management, George Stiubianu, Mihaela Dascalu, Alexandra Bargan, Carmen Racles, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://www.rsc.org/events/detail/43710/
8. Innovative Approach and Recent Developments in Materials Science & Nanotechnology, American Association for Advances in Functional Materials AAAFM UCLA 2021, 18-20 august 2021 (conferinta online), First-Principles Calculations of the Energy Flux for Bioinspired Personalized Thermal Comfort Wearables, George Stiubianu, Alexandra Bargan, Mihaela Dascalu, Carmen Racles, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://aaafm.org/ucla2021/
9. Materials, Methods & Technologies, 23rd International Conference Burgas, Bulgaria, 19-22 august 2021 (conferinta online), Passive Heating and Cooling for Bioinspired Personalized Thermal Comfort in XXIst Century Wearables, George Stiubianu, Mihaela Dascalu, Alexandra Bargan, Carmen Racles, Adrian Bele, Codrin Tugui, Cristian Ursu, Maria Cazacu, https://www.sciencebg.net/en/conferences/materials-methods-and-technologies/
10. 13th International Conference on Physics of Advanced Materials, ICPAM-13, Sant Feliu de Guixols, Spain, 24-30 octombrie 2021 (conferinta participare fizica), Developments in Functional Materials for Energy-Efficient Thermal Comfort, George Stiubianu, Cristian Ursu, Adrian Bele, Codrin Tugui, Alexandra Bargan, Mihaela Dascalu, Carmen Racles, Maria Cazacu, https://icpam.ro/
11. MACRO Iasi 2021, 7-9 octombrie 2021 (conferinta format mixt), Energy-Efficient Dynamic Polymer-Based Nanocomposites for Thermal Comfort, George Stiubianu, Cristian Ursu, Codrin Tugui, Adrian Bele, Alexandra Bargan, Mihaela Dascalu, Carmen Racles, Maria Cazacu, Aurelian Ciobotaru, https://www.icmpp.ro/macroiasi2021
12. XXXIIth edition of the International Congress under the slogan “By promoting excellence, we prepare the future” Apollonia, Iasi, 28 Februarie 2022 (online), “Advanced nanocomposite polymer materials for energy-efficient dynamic self-thermal comfort”, George Stiubianu, Cristian Ursu, Mihaela Dascalu, Alexandra Bargan, Adrian Bele, Codrin Tugui, Carmen Racles, Maria Cazacu.
13. 12th International Conference on Materials Science and Engineeering BRAMAT 2022, Brasov, Romania, 9-12 Martie 2022, “Preparation of Bioinspired Thermal Comfort Nanocomposites and Calculation of Heat Flux Using First Principles”, George Stiubianu, Alexandra Bargan, Mihaela Dascalu, Adrian Bele, Codrin Tugui, Cristian Ursu, Carmen Racles, Maria Cazacu.
14. INVENTICA 2022, Inventics International Conference, The 26th edition, 22-24 Iunie 2022, Gheorghe Asachi Technical University, Iași, Romania, “Dynamic Dual Mode Materials for Human Thermal Comfort”, George Stiubianu, Alexandra Bargan, Mihaela Dascalu, Adrian Bele, Codrin Tugui, Cristian Ursu, Carmen Racles, Maria Cazacu.
15. Tenth international conference on Electromechanically Active Polymer (EAP) transducers & artificial muscles, EuroEAP 2022, Chianciano Terme, Italy, 7-9 July 2022, “Bioinspired compliant mechanism valve with low voltage dielectric elastomers”, George Stiubianu, Adrian Bele, Alexandra Bargan, Mihaela Dascalu, Alina Soroceanu, Ana-Maria Macsim, Maria Cazacu.
Patent applications:
The invention patent application no. A00419/18.07.2022 was sent to OSIM (State Office for Inventions and Trademarks/Oficiul de Stat pentru Invenții și Mărci) for registration together with the related documents for the registration of the patent application titled: "Procedure for obtaining a layered composite material for regulating human thermal comfort"/"Procedeu de obținere a unui material compozit stratificat pentru reglarea confortului termic uman". The request was submitted by the members of the project team as inventors. It describes a process for obtaining a human thermal comfort regulation system made of a layered composite material consisting of a polymer layer and a patterned reflective film for infrared radiation (IR), calendered between a layer of textile material and a layer of porous medical polyethylene. The composite material obtained is low-cost, durable and has the ability to modulate an IR radiation flux of up to 40 W/m^2.
