Hi,

Electron microscope follows the same ideas of optical microscope, but uses electrons instead of light;“Lens” here are not the optical materials (like glass), but electrical field.

A Scanning Electron Microscope uses a beam of electrons to scan the surface of an object to create an image detailing the topography and composition of the object’s surface. 

A Transmission Electron Microscope is used to magnify objects. It aims a beam of electrons onto the object to form a magnified image called a micrograph.

In  SEM an electron beam is focused into a small probe and is rastered across the surface of a specimen.Several interactions with the sample that result in the emission of electrons or photons occur as the electrons penetrate the surface.These emitted particles can be collected with the appropriate detector to yield valuable information about the material.The most immediate result of observation in the scanning electron microscope is that it displays the shape of the sample.The resolution is determined by beam diameter.

In transmission electron microscopy (TEM), a beam of highly focused electrons are directed toward a thinned sample (

Both are different techniques and has their own superiority in particular analysis.  SEM is superior over TEM in studying surface morphology, while TEM goes insight of the material and can give better information.  

It depeonds on what you want.

all in all. I think TEM could be more effective than SEM.

By TEM you could investigate inside of your materials and as an example exploring dispersion of any kinds of additives(esp nano additives)

But dont forget that TEM is more expensive!!!

TEM give more reliable results interms of dispersion especially when the reinforcement is of nanosize, that will be of enhanced clarity than XRD. SEM is good when you are discussing about the surface morphology.

TEM image helps to find out the dispersion of any phase in a polymeric medium. In addition, a special advantage of TEM image over SEM is to distinguish two different materials of even same size (nanofillers) through SAED pattern.  Also, you can calculate the lattice space from HRTEM image and etc. Whereas, SEM image supports to provide more information on surface morphology.

in synthesise polymerizable surfactant, i used  of SEM and  I could not get TEM. One referee of my thesis , he asked  the following question:

(Please provide the reason of using SEM to study the morphology of emulsion particles rather than TEM? )

I do not know what to say. What answer to give him . I do not really know.

You Help ME Please.

In general, TEM is better in terms of resolution and ability of investigating internal structure. Electron diffraction is also possible to investigate crystal structure. However, sample for TEM must be very thin and the information in the depth direction is quite limited. On the other hand, samples for SEM is not so limited about the size in the three dimensional direction. Moreover, one SEM image can record focused information even when the sample has large dimension in the thickness direction. You can observe from the top to the bottom of relatively thick sample at one time. This advantage is better than optical microscopy with the lower resolution.

TEM involves transmission of the electron beam, so very thin specimens are required (as per Masatoshi Tosaka comment). Specimen preparation and mounting is difficult and staining with higher atomic number materials may be required for contrast, or a vacuum sputtered replica can be formed. In viewing through a specimen TEM can reveal internal structures. The resolution (magnification) is better than SEM.

SEM involves reflection from a surface with some penetration into the specimen. The image recorded is a surface image so features introduced during specimen preparation by cutting for instance need to be controlled. Internal features can be viewed after selective etching with solvent, oxidising reagent or physical ablation. The electron beam needs a means to be conducted from the focus point, so often a conducting coating such as gold, or more quickly a graphite spray, must be applied to avoid over exposure due to charge build-up. Field emission SEM allow lower voltage and less vacuum offering imaging without coating. SEM has lower resolution than TEM, though ease of specimen preparation is a factor in choice of technique.

Optical microscopy has lower resolution/magnification than TEM or SEM due to the diffraction limit resulting from the relatively long wavelength of light. Depth of field is reduces compared with SEM. Ultraviolet light (shorter wavelength) increases resolution before the diffraction limit is reached. Newer forms of fluorescent ultraviolet microscopy have resolution approaching atomic scale, and involve techniques to avoid the diffraction limit.

SEM will not give real image and it will give external shape only.  TEM will give real image, external shape and internal structure.

Some times they are complementary. For instance, by SEM you can see the surface or cross morphology and by TEM you can observe specific particles and dimmension of your emulsions.

If you are using a surfactant to improve the distribution of some particles TEM will provide you more information... I suggest you to respond that by SEM seems that particles appear like you see but further studies should be done by TEM to confirm this point in future works.

Although SEM images are 3-D & are accurate representations while TEM pictures are 2-D & may need some interpretation, but as far as resolution & magnification are concerned, TEM has more advantages compared to SEM.

TEM and SEM are complementary microscopies, as stated by Marina., along with the variations of optical microscopy. SEM views surfaces, while TEM views the interior of extremely thin films. When there is a choice in selection of TEM or SEM, the  nature of the material and specimen preparation are a determinants. The thin film required for TEM generally requires an ultra-microtome and mounting on a grid support is difficult. SEM may require surface etching or freeze fracture, plus a conductive coating. In both TEM and SEM, the electron beam can damage the specimen during observation. Microscopies reveal structures according to specimen preparation, what you see is what you have made, both structures and artefacts.

Hi,

Electron microscope follows the same ideas of optical microscope, but uses electrons instead of light;“Lens” here are not the optical materials (like glass), but electrical field.

A Scanning Electron Microscope uses a beam of electrons to scan the surface of an object to create an image detailing the topography and composition of the object’s surface. 

A Transmission Electron Microscope is used to magnify objects. It aims a beam of electrons onto the object to form a magnified image called a micrograph.

In  SEM an electron beam is focused into a small probe and is rastered across the surface of a specimen.Several interactions with the sample that result in the emission of electrons or photons occur as the electrons penetrate the surface.These emitted particles can be collected with the appropriate detector to yield valuable information about the material.The most immediate result of observation in the scanning electron microscope is that it displays the shape of the sample.The resolution is determined by beam diameter.

In transmission electron microscopy (TEM), a beam of highly focused electrons are directed toward a thinned sample (

thanks all

thanks all

thanks all