![Figure 1. a) Schematic representation of the PVP – Fe-aminotriazole composite where the blue dashed lines represent the hydrogen bonds. b) TEM image of the composite film with regular striped patterns. c) Temperature dependent magnetic behavior of the composite.[24]](/figures/figure-1-a-schematic-representation-of-the-pvp-fe-11cv6izs.webp)
![Figure 7. a) Schematic representation of the synthesis of the Hoffman-like clathrates [Fe(pz){M(CN)4}] within chitosan beads. Thermal variation of T for the nanocomposite [Fe(pz){M(CN)4}]-chitosan beads for b) M=Ni; c) M=Pd; d) M=Pt and e) a nanocomposite film of [Fe(pz){Ni(CN)4}]-chitosan.[44]](/figures/figure-7-a-schematic-representation-of-the-synthesis-of-the-1f2hkyt9.webp)
2; b) PGMA-trz and MPEG-trz; c) T for [Fe II(MPEGtrz)1.5(NH2trz)1.5](BF4)2; d) H2salten ligand ; e) and f) polystyrene-Tp Fe II complexes.[72–76]](/figures/figure-19-a-feii-terpy2-pp-clo4-2-b-pgma-trz-and-mpeg-trz-c-2x6rf8wj.webp)
![Figure 11. Schematic representation of a bilayer SCO-polymer composite cantilever with electrothermal actuation and the experimentally observed variation of the cantilever tip position (in ambient conditions) upon the application of an alternating current.[51]](/figures/figure-11-schematic-representation-of-a-bilayer-sco-polymer-pmv6u4nn.webp)
![Figure 12. a) Schematic structure of the bilayer SCO-piezoresistive cantilever and (b) photos of the prefabricated polyimide/constantan alloy/polyimide stress-sensitive plate before (left) and after (right) drop-casting of the SCO-active composite. c) Bistable voltages of the Wheatstone bridge upon 4 thermal cycles.[52]](/figures/figure-12-a-schematic-structure-of-the-bilayer-sco-14npjgyi.webp)
![Figure 18. 3D printed objects of polymer composites of the SCO complex [Fe(NH2trz)3]SO4.[68]](/figures/figure-18-3d-printed-objects-of-polymer-composites-of-the-280n97p9.webp)
Q2. What is the common name for dendrimers?
Dendrimers are globular-shaped, highly branched macromolecules with controlled molecular weight, size and number of functional groups, due to their well-defined synthetic method based on iterative reactions.
Q3. What is the key interest of this approach?
The key interest of this approach is the possibility to create arbitrary planar and threedimensional geometries, which are otherwise not accessible using spin crossover complexes.
Q4. What are the promising sites for dendritic molecules?
The multiple reactive sites for molecular attachment such as the periphery, core, branching points or cavities in coordination with their micellar properties make dendritic molecules very promising for various applications.
Q5. What is the advantage of mixing polymers with preformed SCO powders?
Mixing polymers with preformed SCO powders (including both micro- and nanocrystals, nanorods, etc.) provides obviously the advantage of better control over particle morphology and SCO properties.
Q6. What is the effect of the SCO nanoparticles on the cellulose?
The SCO nanoparticles were randomly dispersed along the surface of the cellulose fibers - stabilized electrostatically due to the interaction between the hydroxyl groups of the cellulose and the metal cations of the SCO complex.
Q7. What is the deeply investigated compound?
The complex [Fe(ODT)3] 2+, with various counter-anions, is probably the most deeply investigated compound capable to form gels in different solvents.
Q8. What is the effect of the spin transition on the polymer matrix?
In this composite, the large strain associated with the spin transition is expected to give rise to an electrical response (voltage or current) due to the piezoelectric properties of the polymer matrix.
Q9. What were the two parameters that were essential to obtain a material with optimal mechanical properties?
Two parameters were essential to obtain a material with optimal mechanical properties: the nature of the alkoxysilane and the exposure time.
Q10. What is the role of graphene in the development of SCO composites?
In this context, emerging graphene-based SCO composites will likely play also an important role, exploiting couplings to the unique electrical, mechanical and thermal properties of graphene.
Q11. What is the effect of the loss of water molecules on the dendritic SCO complex?
They display a change of spin state of iron ions above room temperature, albeit this change is irreversible after the first heating process in all three dendritic Fe(II) complexes, most likely due to the irreversible loss of water molecules ‘bonded’ to the dendritic ligands (through hydrogen bonding etc.).
Q12. Why is it assumed that these types of compounds are efficient gelators?
It is commonly assumed that these types of compounds are efficient gelators due to lipophilic interactions between the aliphatic part of the SCO complexes and the chosen solvents.
Q13. Why is the EPR more pronounced with the chloride anions?
This effect is more pronounced with the chloride anions due to their inherent small size resulting in a closer chain packing with higher interactions within the bilayers.
Q14. How did the authors obtain a flexible polymer nanocomposite?
This way they obtained a flexible polymer nanocomposite material with PDMS protection, which provided long-term stability to the material (> 80 days), prevented its decomposition when immersed in hot water and allowed to preserve its SCO properties over >15 thermal cycles.
Q15. What is the spectra of the PF6 - and ClO4?
The EPR spectra of the PF6 - and Cl- complexes show the presence of three different magnetic iron species (two HS and one LS); while for the ClO4 - only one HS and LS iron center is observed.
Q16. What is the first example of a strain-coupling of a polymer to an?
This work is the first example for strain-coupling of SCO to electroactive polymers (EPA) in a composite materials, with interesting perspectives for the development of sensors, actuators and energy harvesting devices.