## 4 Future Research  
As climate change and global warming increasingly pose challenges to modern society, the scientific community is also following suit. This trend is evident in the field of CNT research, which is increasingly focused on the development of sustainable materials and production methodologies. Significant efforts are dedicated to exploring bio-surfactants derived from organic sources that minimize environmental impact. These bio-based surfactants represent a promising avenue for reducing the ecological footprint of nanomaterial production and application, aligning with global sustainability objectives. A recent study proposes using bio-approach to functionalize CNTs and carbon nanofibers (CNFs) using proteins such as soy protein isolate (SPI) and gelatin [127]. This method aims to enhance dispersibility and material properties. While SPI has shown promising effectiveness in improving carbon nanofiber dispersion, its potential as a bio-surfactant has only been qualitatively assessed so far, typically through optical or microscopic observation. However, there is a lack of quantitative analysis to systematically evaluate its efficiency in functionalizing nanofillers, controlling particle size and distri \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
** Composites** & **Formulation** & **Output** \\ \hline \multirow{3}{*}{Cement + p-CNTs} & Pristine MWCNTs & Improved strength over reference sample, but p-CNTs showed superplasticizer & \\  & & & agglomeration, affecting properties negatively \\ \hline \multirow{3}{*}{Cement + c-CNTs} & Carboxyl-functionalized MWCNTs dispersed with superplasticizer & Improved flexural (15.7\%) and compressive strength (16.9\%) through crack-bridging mechanism \\ \cline{1-1} \cline{2-3}  & Plasma-modified MWCNTs dispersed with superplasticizer & Highest flexural strength (37.1\% increase) and compressive strength (24.3\% increase) due to enhanced dispersion and bridging \\ \hline \hline \end{tabular}
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Table 10: Modified MWCNTs in cement composites. (Summary of the study of [PERSON] et al. [126]). \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
** Composites** & **Formulation** & **Output** \\ \hline \multirow{3}{*}{MWCNTs + Cement (with DMF)} & MWCNTs dispersed with DMF, mixed with cement using ultrasonication & Increased compressive strength (77.2 MPa) and flexural strength (11.2 MPa); DMF dispersion improved mechanical properties \\ \cline{1-1} \cline{2-3}  & MWCNTs mixed with cement without DMF & Lower mechanical strength than with DMF; MWCNTs contributed to improved fracture resistance \\ \hline \hline \end{tabular}
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Table 9: MWCNT-reinforced cement composites. (Summary of the study of [PERSON] et al. [124]). bution, and enhancing the mechanical performance of bulk composites. Some studies have already focused on that aspect [127; 128; 129; 130]. One of these studies by [PERSON] et al. performed a quantitative analysis to measure the impact of soy protein isolate (SPI) as a bio-surfactant. The study found that the nanocomposites with SPI-treated CNTs showed notable improvements in tensile modulus, strength, and fracture toughness by 27%, 24%, and 32%, respectively, at a 1.0 wt% CNT loading. SPI outperforms sodium dodecyl sulfate (SDS) in terms of dispersion efficiency and stability. The SPI-CNTs exhibit less agglomeration and more stable particle size distribution, contributing to the uniform distribution of CNTs within the composite. These results highlight the potential of SPI as an effective and environmentally friendly surfactant for improving the dispersion and overall properties of CNT-reinforced composites, suggesting its suitability for industrial applications in fields requiring high-performance materials [130]. Another study proposes a new method inspired by mussels to enhance the interface between carbon fibers (CFs) and epoxy matrix in carbon fiber-reinforced polymer (CFRP) composites using polydopamine (PDA) and carbon nanotubes [131].