Non-Functionalized Colloidal Poly(methyl methacrylate) (PMMA) Nano-/Microspheres
CV< 3% for nanospheres from 300 nm to 1 μm;
CV< 5% for microspheres from 5 μm to 20 μm;
CV< 15% for microspheres from 50 μm and above;
The roundness of both our PMMA nanoparticles and microparticles is above 0.980;
Provided in Milli-Q water;
Concentrations available: 10 - 50 mg/ml (i.e. 1 - 5 % w/v);
Other customized sizes (100 nm - 100 μm) available upon request (lead time: ~3 weeks);
PMMA nanoparticles can be used for many applications similar to those involving polystyrene microparticles but PMMA microparticles are higher in density than polystyrene microparticles.
Scanning Electron Micrographs
High-Resolution Transmission Electron Micrographs of Poly(Methyl Methacrylate) Nanospheres
Zeta Potential Measurement Results of Poly(Methyl Methacrylate) Microspheres
Fourier-transform infrared spectroscopy (FTIR) Results
How do we measure the CV Values and reveal the real size distributions?
Through the years of working with nano-/microspheres, our researchers and technicians fully understand the importance of the size distributions from batch to batch. In the field of size characterizations, there are mainly two methods, scanning/transmission/scanning transmission electron micrographs (SEM/TEM/STEM) and dynamic light scattering (i.e. DLS). Unfortunately, we found DLS are unsuitable for accurately determine the size distributions of nano-/microspheres when compared to SEM/TEM/STEM techniques.
DLS results are closely related to colloidal stability, and as an inevitable result, the size distributions will not be accurate for large-sized nanoparticles. For nanoparticles below 100 nm, the hydrodynamic sizes become relevant. However, for nanoparticles around or above a few hundred nanometers, colloidal stability is greatly affected by the role of gravity. In comparison, the SEM/TEM/STEM images are based on dry samples only where higher reproducibility and reliability have been seen through numerous studies in our case and in the literature.
DLS cannot distinguish between nanoparticles themselves and the aggregates of surfactants. As most of our colloidal nano-/microspheres have a trace of surfactants purposely added in the system for longer lifetime, DLS becomes unsuitable for direct size measurements unless the nano-/microspheres are washed at least three times with the Milli-Q water or de-ionized water to fully remove any trace of surfactants. Similarly, the nano-/microspheres due to inefficient re-suspension also distort the DLS results; for instance, a couple of aggregated 100 nm nanoparticles might be seen as 200 nm or 300 nm nanoparticles under DLS measurements.
DLS cannot give any insight into the shape or the spherical degree of nano-/microspheres. Irregularly-shaped particles and perfectly spherical particles can be interpreted the same under DLS measurements.
As a result, we use SEM/TEM/STEM techniques instead of DLS measurements as our routine quality control method. We routinely take at least 10 electron micrographs and process them with ImageJ for size distributions as well as the CV value. This is also the reason that we typically include a couple of representative SEM/TEM/STEM images with our products when delivered to our clients. We wish to reveal the real size distributions and let the clients visualize the images of nano-/microspheres directly instead of viewing the fitted curves indirectly.
Daily Exchange Rates
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1. We accept both online purchases at our online store or Amazon stores and invoiced orders (Net 30 Terms). In-stock items will be dispatched within 1-3 business days and the lead time for customized orders will be evaluated on a case-by-case basis.
2. Orders destined for the US will be shipped from one of our two US offices. Orders destined for the UK and the EU will be shipped from the UK office. Orders destined for Canada will be shipped from our Canadian headquarters. No duties or any additional taxes for the orders delivered to Canadian, US, and UK addresses, regardless of the selected sales channel. For other International shipping addresses, recipients are responsible for local duties and taxes.
3. Free exchanges or full refunds will be offered within 30 days after the order fulfilment without any questions asked if the ordered items fail to meet customer expectations.