Thermogravimetric analysis (TGA). For estimating the thermal stability of the systems and the amount of capping agent present in our samples, TGA were carried out under inert atmosphere. Bare MnPS 3 in bulk form and both capping agents were analysed by this technique and used as reference samples (Fig. and ESI Fig. ). Afterwards, the MnPS 3 @H 2 O, MnPS 3 @PVP and MnPS 3 @PEI systems were evaluated under the same experimental conditions Fig. . From room temperature until 200 o C weight losses in all samples are related to absorbed water, which is significantly larger in exfoliated systems due to occluded water molecules between the layers. Upon a further increas of the temperature, bulk MnPS 3 does not suffer any significant weight loss until ~480 o C when the inorganic solid starts its decomposition that takes place in the 480-515 o C range. This drop is shifted between 460-485 o C when the material is exfoliated. However, MnPS 3 @PVP presents a sharp weight loss at ~375 o C very similar to the one observed in the TGA of pure PVP (ESI Fig. ), while MnPS 3 @PEI shows a first small continuous decrease between 180-250 o C and a second larger one, but also very gradual, between ~250-450 o C, that contrast with the sharp single step observed at ~320 o C for pure PEI (ESI Fig. ). These results support the presence of the organic polymers in the composites once more and evidence the existence of stronger interactions between PEI and the inorganic flakes than for PVP. In more detail, the first gradual thermal decomposition of MnPS 3 @PEI (~180-250 o C range) seems to point out to a small amount of physisorbed PEI, while the second (~250-450 o C range) supports the presence of a significant amount of PEI strongly interacting with the inorganic layers probably due to the presence of positively charged amino groups of the polymer interacting with S atoms of the flake. Similar trends have been observed in PEI wrapped graphene oxide layers. Finally, for the calculation of the polymeric content, it is important to consider that from 400 o C, there is an overlap between polymer and MnPS 3 decomposition. In order to avoid the overestimation of the polymeric content in the hybrid systems, we have considered a 17% weight loss at 675 o C, strictly related to the degradation of the inorganic exfoliated material, once H 2 O content has been already eliminated below 200 o C (Calculated from MnPS 3 @H 2 O TGA, Fig. ). Taking all these considerations, a ~21% and a ~14% of polymer content is assessed for MnPS 3 @PVP and MnPS 3 @PEI, respectively. A summary of the water and polymer percentages in all samples is presented in Table . X-ray powder diffraction (XRPD). Crystallinity of the samples was investigated through XRPD. Diffraction patterns of the exfoliated samples resemble that of bulk MnPS 3 (Fig. ), denoting that main crystalline structure is preserved. Peak (001) at 2θ = 13.6 o corresponding to an interlayer distance of d=0.65 nm in bulk MnPS 3 , is maintained unaltered in MnPS 3 @H 2 O but a clear broadening indicates a drop in the periodicity along the c-axis, which is due to the decrease in the number of stacked layers. However, new diffraction peaks emerge at lower angles once the material is wrapped by the organic polymers (highlighted area in Fig. ). These new peaks are related to new interlayer spacing for the slabs of MnPS 3 . 26 Thus, in the case of MnPS 3 @PEI, the main peak appears at 2θ =7.8 o corresponding to an interlayer spacing of 1.14 nm and in the case of MnPS 3 @PVP at 2θ = 3.22 o indicating a new interlayer distance of 2.74 nm. As these polymers can be arranged in different ways around the flakes, more than one peak can appear sometimes as observed for PVP. However, their intensities are much lower than those just mentioned, suggesting a main preferential ordering between the layers driven by the intense interaction between the capping agents and MnPS 3 layers, as was deduced by the IR spectra. It is important to mention that the assignment of these low angle diffraction peaks to K + or Li + intercalated MnPS 3 can be excluded by the measurement of the corresponding diffraction patterns of these intercalated systems. (ESI Fig. )