What are nanoparticles?
Nanoparticles are materials with key dimensions typically 1–100 nm. At this scale the surface-to-volume ratio explodes, so surface chemistry dominates: particles stick together more easily, react faster, scatter light differently, and can even show quantum-size effects (e.g., colloidal Au appearing red/purple vs bulk yellow). Small shifts in impurities, size distribution, crystal phase, or surface ligands can dramatically change performance—great for tuning properties, risky if specs aren’t controlled.
Where you’ll see them:
Conductive inks/pastes (Ag, Cu), battery oxides/carbons, photocatalysts/pigments (TiO₂, ZnO), biomedical probes (Au, Fe₃O₄), sensors, coatings.
Where do nanoparticle “grades” come from?
Unlike classic reagent grades (AR, CP, HPLC), nanoparticle “grades” are usually applicationdefined packages of QC thresholds and form factors. Vendors qualify lots against size distribution (TEM/DLS), phase (XRD), surface chemistry (XPS/FTIR/TGA), purity (ICPMS), zeta potential, and residuals to meet specific use cases.
Why the nanoscale matters:
- Chemical reactivity & catalysis: More active sites due to high surface area; size and facet exposure control activity/selectivity.
- Optical properties: Noble metal colloids show surface plasmon resonance (color changes with size); some semiconductors show size‑dependent band gaps.
- Magnetism & electronics: Superparamagnetism in Fe₃O₄ ≈10~20 nm (size threshold depends on chemistry and shape).; improved conductivity/ink jetting in conductive inks.
- Mechanics & barriers: Nano‑fillers strengthen polymers and improve barrier/UV properties.
How nanoparticles are supplied in reagent catalogs
Dry nanopowder:
Primary particles in the nano range, often forming soft agglomerates in the dry state. Maximum flexibility for custom dispersions, but may require deagglomeration (sonication, milling) and careful handling to avoid dust exposure.
Colloidal/dispersion form:
Nanoparticles dispersed in water, ethanol, ethylene glycol, toluene, etc., typically stabilized by citrate, PVP, PEG, or surface functional groups (–COOH, –NH₂, –OH). Ready-to-use, less dusting, but solvent choice and shelf life matter.
Surface-functionalized variants:
Tailored interfaces for bioconjugation, polymer compatibility, or catalyst deposition.
Core properties & how we qualify them (tests → applications)
Core property | How we qualify it | Why it matters | Application examples |
Purity & trace metals | ICP-MS/ICP-OES (ppm Fe/Ni/Cu/…) | Shorts, corrosion, catalyst poisoning, toxicity | Ag inks need Fe/Ni/Cu very low (e.g., ≤10 ppm each) (example target) |
Size & distribution | TEM/SEM (core), DLS + medium/protocol (hydrodynamic) | Packing, optics/electronics, reactivity; D90/D50 ≈ 1.2–1.6 post-dispersion | Narrow Ag NPs for printing; tight Fe₃O₄ for imaging |
Surface area | BET (with degas details) | Reactivity & sinter rate | High-BET TiO₂ for photocatalysis |
Surface chemistry/ligands | XPS/FTIR, TGA-MS (ligand load) | Dispersion, biocompatibility, active site access | PVP-capped Ag for stable inks; ligand-free oxides for catalysis |
Phase/crystallinity | XRD (Rietveld) | Functional properties depend on phase | Anatase vs rutile TiO₂ |
Agglomeration/dispersion | Zeta potential vs pH/ionic strength; post-sonication DLS | Processability & shelf stability | Ready-to-use sols for inks/bio |
Residues/volatiles | LOD/TGA | Processing yield, VOC, moisture | Low LOD for screen-printing |
Bioburden/endotoxin | Plate count, LAL | Assay integrity & safety | Biomedical research grade |
Terminology：
- D10/D50/D90: Percentile diameters from the size distribution. D50 is the median (50% of particles are ≤ this size). D10 and D90 bound the lower/upper tails; the span (D90 - D10) reflects distribution width.
- TEM vs DLS: TEM reports dry core size; DLS reports hydrodynamic diameter (core + solvation + ligands/soft shells), so DLS is usually larger.
- PDI: Polydispersity index from DLS; ≤ 0.10–0.15 indicates a narrow, often monomodal dispersion.
Comparison with similar terms and grades
Term | What it means | When to choose |
Nanoparticles (NPs) | Umbrella term for 1–100 nm materials | property-first, form-neutral wording early in RFQs/COAs when you want to specify properties |
Nanopowder | Dry form of nanoparticles (can agglomerate) | You’ll control dispersion in-house and need maximum formulation flexibility, or face solvent/shipping constraints. |
Colloidal dispersion/sol | NPs pre-dispersed in liquid with stabilizers | Ready-to-use material for inks/coatings/bio with consistent rheology/printability. |
Sub-micron/micropowder | 0.1–10 µm; not nano | When nano isn’t required for performance |
Trace-metals/electronic/battery grade | Tight ppm, narrow size, phase-pure | Electronics, catalysis, batteries where trace Fe/Ni/Cu, etc. must be controlled |
Biomedical grade | Adds endotoxin/bioburden + bioligands | Cell work, imaging R&D. Specify LAL threshold, dispersion medium, ligand chemistry, and sterility/bioburden notes. |
How to choose a nanoparticles product
1) Define application → basic R&D | electronics/catalysis | bio/cell.
2) Set impurity limits (ppm) → include critical elements (e.g., Fe/Ni/Cu for Ag inks).
3) Pick size window & distribution → D10/D50/D90 or PDI plus method & medium.
4) Choose surface state → ligand-free vs defined ligand; removal plan if needed.
5) Require evidence → ICP table, TEM + DLS with dispersion protocol, BET, XRD, LOD/TGA, zeta, LAL (if bio).
6) Pilot test → dispersion trial + small-scale performance check; then lock spec.
FAQ
Why is DLS larger than TEM?
DLS measures hydrodynamic size in a specific medium (solvent shell + aggregates). TEM shows dry core size. Report the medium and protocol with DLS.
Metal-basis vs trace-metals basis?
Metal-basis % says how much target element is present; doesn’t list remaining contaminants. Trace-metals basis lists ppm impurities—crucial for electronics/catalysis/batteries.
How to break agglomerates?
Tune pH/ionic strength, add compatible dispersant, use controlled sonication; verify with DLS/TEM.
Can I remove ligands by calcining?
Often yes, but you may grow particles or change phase. Re‑check XRD and size afterward.
My Au colloid color shifted—what happened?
Plasmon peak changes with aggregation, size, or medium refractive index. Check salt level, pH, and surfactant.
Powder vs pre-dispersion?
Dispersions add solvent + stabilizers (check concentration, ligand, viscosity, shelf life).
Are nanoparticles the same as quantum dots?
Quantum dots are a subset of semiconductor nanoparticles with size‑tunable photoluminescence; they require specialized surface chemistry/handling.
Tips & cautions
- Storage: nanopowders often hygroscopic; keep dry/inert; avoid dispersion freeze–thaw.
- Cross-contamination: use low-shed tooling (ceramic/zirconia); avoid steel if Fe/Ni/Cu are critical.
- Verify after processing: calcine/cleaning can grow particles or change phase—recheck XRD/size.
- Safety: treat as respirable dust; follow PPE and engineering controls per EHS.
Why choose Aladdin？
We make rigorous, transparent quality control our core. Every lot is tested against application-specific standards, and the COA goes beyond numbers to disclose the methods and conditions so you can reproduce results on site. We also provide lot traceability and change control to minimize uncertainty during scale-up and mass production.
View all Nanoparticles Products