Measuring the Thermal Conductivity of Nanomaterials
Trident Thermal Conductivity Instrument, equipped with the MTPS sensor, ideal for measuring nanomaterials and the thermal mapping of composites.
The Modified Transient Plane Source (MTPS) method developed by C-Therm provides the optimal choice for researchers in characterization the thermal conductivity of nanomaterials. Such materials are expensive and time-consuming to produce in the development phase. The MTPS has a small volume requirement of 1.5 mL, which is convenient for quick measurements, especially given the cost of large volumes of nanoparticles. The method’s simplicity allows researchers to quickly and easily characterize their samples, with no need for regression analysis. Additionally, the single-sided sensor is the only method that allows for the thermal mapping of a sample’s performance to better understand the dispersion of nanomaterials in a polymer matrix.
An epoxy resin that has been filled with conductive metal nanoparticles to increase thermal conductivity. This was done unevenly for the purpose of creating a thermal map.
A thermal map of the nanoparticle-filled epoxy resin. The high thermal conductivity correlates to a high concentration of nanoparticles. This map demonstrates the uneven nature of the filler. This is only possible with the MTPS.
An example of settling detection; the top of the composite has a visibly lower particle concentration that the bottom, and this can be detected using thermal conductivity measurments possible with the single-sided MTPS.
The thermal conductivities of common nanomaterials and metals. Nanomaterials are often used as filler materials to improve the heat transfer of composites.
Single-walled (left) and multi-walled (right) carbon nanotubes (CNT) which are often used as a filler material to increase thermal conductivity.
How Nanomaterials Influence Thermal Conductivity
Nanomaterials offer unique electrical properties, extraordinary strength and great efficiency in heat conduction. Application areas for nanomaterials include electronics, optics, medicine and architecture – offering tremendous potential for ground-breaking discovery. The effective thermal conductivity is often considered a critical performance attribute of the material.
Haydale Composites Solutions Ltd.
The C-Therm TCi has been a key piece of testing equipment at Haydale, providing fast and accurate thermal conductivity measurements for our product development of nanocomposites. Having this capability has allowed a better understanding of the dispersion of nanomaterials in polymer matrices through thermal mapping sample surfaces. The support and customer service from C-Therm has been excellent over the years, we look forward to dealing with them again in the near future.”
Stuart Sykes, Haydale Composites Solutions Ltd. (Sector: Nanocomposites)
We wanted something that was going to measure small volumes and do it in a rapid and easy format and the TCi Thermal Conductivity instrument was perfect for our needs. The thing I like most about the TCi is it is extremely easy to use."
It is now more than four years that we are using the C-Therm Thermal Conductivity Meter. The instrument plays an important role during the characterizations of the polymer and graphene composites, both, for R&D projects and Quality Control purposes. Practically a maintenance free instrument, it is accurate and easy to use in the same time.
Dispersion and Thermal Conductivity of Carbon Nanotube Composites
The following is a case highlight from a paper that can be read here.
Recent work, performed by Florida State University and Texas Tech University, leveraged the MTPS’ capabilities to help investigate different methods used to shorten carbon nanotubes (CNTs) for improved dispersion with maintained thermal conductivity. Single walled CNTs were mechanically cut to produce short and open-ended fullerene pipes. A separate sample set was then acid-oxidized to shorten the CNTs.
Shortened nanotubes were found to improve dispersion into polymer matrices and resulting in higher thermal conductivity.
Mechanically chopped CNTs performed significantly better than acid oxidized samples, which resulted in degraded CNTs and an overall lower thermal conductivity of the resin composite.
Hybrid Nanocellulose/Carbon Nanotube/Natural Rubber Nanocomposites with a Continuous Three-Dimensional Conductive Network
Abstract from original publication: In this study, the hybrid effect of nanocellulose/carbon nanotube (NCC/CNT) reinforcement on natural rubber (NR) nanocomposites was investigated. To this end, three series of NR nanocomposites were prepared: NCC/NR, CNT/NR and NCC/CNT/NR. First, the nanocomposites morphology and the filler–rubber interactions were studied using scanning electron microscopy (SEM) and the swelling behavior in toluene, respectively. The results showed that the presence of NCC improved the NCC/CNT hybrid filler dispersion forming a 3D network, while the presence of CNT increased the filler–matrix interaction. The curing results also confirmed that the degree of crosslinking increased when hybrid fillers were used, but the curing time was not modified. In addition, it was observed that using a NCC/CNT hybrid system led to superior mechanical properties, dynamic mechanical properties and thermal conductivity than each material used separately. When 10 phr hybrid filler (with a filler ratio of 1) was added to NR, the tensile strength, modulus at 300% elongation (M300), storage modulus at 10% strain and thermal conductivity were all increased by 57%, 137%, 120%, and 30%, respectively. The results also showed that the NR nanocomposites properties can be controlled by tuning the NCC/CNT filler ratio. [1]
Thermal conductivity, heat diffusivity, and heat capacity of the nanocomposites were determined using a C-Therm TCi thermal conductivity analyzer. The samples were pre-pared in cylinders of 25.4 mm in diameter and 12.5 mm in thickness. Thermal conductivity measurements were performed at least five times for each compound to report average values. [1]
Using Nanoparticles to Improve Electronic Thermal Management
As electronic devices rapidly develop, questions of effective thermal management continue to grow. In small electronics, the materials selected must have high thermal conductivity to dissipate heat, while also be able to effectively connect the chips being used. One common solution is the use of epoxy composite materials.
Epoxy is a type of polymer resin, that usually has a very low thermal conductivity. Therefore, conductive nanofillers are often used to increase the thermal conductivity, making the epoxy composite an effective thermal interface material (TIM). One common nanomaterial used is called h-BN, or “white graphene” and is used for its high thermal conductivity and high electrical insulation. However, researchers have exfoliated h-BN to form boron nitride nanosheets (BNNS) which also exhibit high electrical resistance as well as having greater thermal and chemical stability.
Two epoxy composites were made, one using 51% h-BN and the other using 51% BNNS, and the conductivity results can be seen below.
Based on these results, the BNNS exhibited better performance as a TIM, since the higher thermal conductivity would more effectively disperse the heat.
This highlights data from Large-scale production of boron nitride nanosheets-based epoxy nanocomposites with ultrahigh through-plane thermal conductivity for electronic encapsulation; click here to read it in full.
Nanomaterials
Recent work, performed by Florida State University and Texas Tech University, leveraged the MTPS’ capabilities to help investigate different methods used to shorten carbon nanotubes (CNTs) for improved dispersion with maintained thermal conductivity. Single walled CNTs were mechanically cut to produce short and open-ended fullerene pipes. A separate sample set was then acid-oxidized to shorten the CNTs.
