Nanomaterials
Glycerol tunes silver nanoparticle size
Open access · cc by · source: Europe PMC
Silver nitrate reduced in 10–100% glycerol with PVP at room temperature gives plasmonic Ag nanoparticles from ultra-small (~1.8 nm) up to ~160 nm.
Study at a glance
- Design
- Other — Room-temperature PVP/glycerol synthesis of size-tunable silver nanoparticles
- N
- Nanomaterial synthesis method — no sample N
- Population
- Silver nanoparticles formed in aqueous glycerol/PVP
- Outcome
- Glycerol-dependent particle size from ultra-small to ~160 nm
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Up to ~60% glycerol, absorption stayed consistent and ultra-small particles (<10 nm) formed in one step. Above ~70–80% glycerol, SPR and size rose, reaching 10–160 nm (particles as small as 1.8 nm and as large as 159 nm at the glycerol extremes). Color intensified with glycerol content.
Methodology
They dissolved PVP in aqueous glycerol (10–100%), added AgNO3, and stirred at 20–25 °C until a yellow plasmon color appeared. Size was measured by UV-vis (410–450 nm SPR), DLS, TEM (~50 particles), and SEM for larger particles. No extra heat, pH swing, or sonication was required.
Limitations
Catalytic or biological performance of the NPs is not the main result. Size statistics use limited particle counts, and glycerol viscosity complicates DLS interpretation at high %. Long-term colloidal stability in water after removing glycerol is not fully mapped.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
TEM of a glycerol/PVP silver synthesis, counting ~50 particles, tracks a solvent knob that UV-vis only sees as SPR. Up to ~60% glycerol, particles stay ultra-small (<10 nm) with a stable 410–450 nm plasmon; above ~70–80% glycerol, SPR and size rise, spanning about 10–160 nm (extremes 1.8 nm and 159 nm). High glycerol viscosity also complicates DLS, so TEM is doing work that a single hydrodynamic diameter cannot.
Evidence for the claim as stated.
TEM and SEM are not interchangeable length scales. The glycerol silver paper uses TEM (~50 particles) for ultra-small (<10 nm) objects and SEM for larger particles as glycerol exceeds ~70–80% and sizes reach tens to 159 nm. Quoting 'electron microscopy showed 10 nm particles' without which microscope and which glycerol fraction mixes those regimes.
Evidence for the claim as stated.
Silver SPR is a size/composition reporter, not a structure determination. GSH-capped Ag develops SPR at 344–354 nm as TEM diameters go 3.20 → 4.83 → 6.19 nm (36/48/72 h). Aqueous glycerol (10–100%) keeps SPR in 410–450 nm and particles <10 nm up to ~60% glycerol, then SPR and size rise above ~70–80% glycerol (about 10–160 nm). Gamma-made Ag/Se/Ag–Se particles are tracked at 406, 518 and 420 nm with mean sizes 10.95, 20.54 and 12.69 nm.
Evidence for the claim as stated.
Steady-state SPR and femtosecond transient absorption are different UV-vis experiments. Glycerol content or stirring time shift a plasmon over minutes to days; the Fe cascade's ~50 fs ISC is already near the instrument response. You cannot transplant an SPR size calibration onto a molecular four-state kinetic model.
Evidence for the claim as stated.
The glycerol silver synthesis is explicit that SEM and TEM cover different sizes. UV-vis SPR stays 410–450 nm and particles stay <10 nm up to ~60% glycerol (TEM of ~50 particles); above ~70–80% glycerol, SPR and size rise toward 10–160 nm (extremes 1.8 and 159 nm) and SEM is used for the larger objects. Catalytic performance of those NPs is not the main result.
Evidence for the claim as stated.
TEM versus SEM is a length-scale choice, not a preference. Ultra-small glycerol Ag (<10 nm) is a TEM problem; SEM is reserved for the larger 10–160 nm branch. GSH Ag TEM diameters of a few nanometres are below what most SEM images of a catalyst or hydrogel are used to claim. Mixing those papers into one 'electron microscopy size' is the error.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
TEM and SEM are not interchangeable length scales. The glycerol silver paper uses TEM (~50 particles) for ultra-small (<10 nm) objects and SEM for larger particles as glycerol exceeds ~70–80% and sizes reach tens to 159 nm. Quoting 'electron microscopy showed 10 nm particles' without which microscope and which glycerol fraction mixes those regimes.
Steady-state SPR and femtosecond transient absorption are different UV-vis experiments. Glycerol content or stirring time shift a plasmon over minutes to days; the Fe cascade's ~50 fs ISC is already near the instrument response. You cannot transplant an SPR size calibration onto a molecular four-state kinetic model.
TEM versus SEM is a length-scale choice, not a preference. Ultra-small glycerol Ag (<10 nm) is a TEM problem; SEM is reserved for the larger 10–160 nm branch. GSH Ag TEM diameters of a few nanometres are below what most SEM images of a catalyst or hydrogel are used to claim. Mixing those papers into one 'electron microscopy size' is the error.
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