## 4 Conclusions  
In summary, anion-\(\pi\) type PNPs were synthesized in this work, significantly improving the dispersion stability of various organic pigments in water through multiple non-covalent bond interactions. The spectral results mentioned above revealed that the interactions between PNPs and pigments were stronger than those among the pigments themselves, effectively weakening the pigment-pigment interactions. Specifically, the anions in the chains of PNPs formed electrostatic interactions or salt-bridge H-bonds with pigments, while the benzene rings established \(\pi\)-\(\pi\) interactions with pigments. These interactions worked synergistically to facilitate the dissociation of the intermolecular \(\pi\)-\(\pi\) stacking backbone or classical H-bond network of the pigments. Furthermore, CMYK water-basedinkjet inks formulated with PNPs-5 demonstrated long-term dispersion stability, excellent weathering resistance, and robust chemical resistance. Overall, anion-\(\pi\) type PNPs show great promise in overcoming the limitations of traditional dispersants, including complex synthesis processes, relatively weak interactions with pigments, and the limited types of applicable pigments. These findings contribute to advancing the structural design of polymeric dispersants and preparing high-performance water-based inkjet inks, offering significant potential for broader applications in industrial production.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/molecules30050975/s1](https://www.mdpi.com/article/10.3390/molecules30050975/s1)]([https://www.mdpi.com/article/10.3390/molecules30050975/s1](https://www.mdpi.com/article/10.3390/molecules30050975/s1)), Table S1 and Figures S1-S7: Characterization of these anion-\(\pi\) PNPs; Table S2 and Figure S8: Characterization of different pigments; Figure S9: UV-Vis spectra of these anion-\(\pi\) PNPs; Figures S10-S12 and Tables S3 and S4: Interactions between anion-\(\pi\) type PNPs and CuPc; Figure S13: \(\zeta\) values of CB mixed with different PNPs, using CB without PNPs as the control group; Figure S14: ATR-FTIR spectra of these anion-\(\pi\) PNPs in the range of 4000-2800 cm\({}^{-1}\); Figure S15 and Tables S5 and S6: Interactions between anion-\(\pi\) type PNPs and R-254; Figure S16 and Tables S7 and S8: Interactions between anion-\(\pi\) type PNPs and Y-180; Figure S17: UV-Vis spectra of organic pigments (a) CuPc, (b) R-254, and (c) Y-180 with PNPs-5 in preferred mixing ratios. Figure S18: Photos of aqueous dispersion of PNPs-5 at 4% content (a) before and (b) after drying. Figures S19-S21: Performance of CMYK four-color water-based inkjet inks; Figure S22: Contact angles of (a) PS, (b) Glass, and (c) Coated paper with water. Figure S23: Photo of printed paper.  
Conceptualization, S.X. and S.Z.; validation, C.S. and S.X.; formal analysis, N.L.; investigation, N.L. and S.X.; resources, C.S. and S.Z.; data curation, N.L. and L.L.; writing--original draft preparation, N.L.; writing--review and editing, D.F., S.X. and S.Z.; visualization, D.F. and L.L.; supervision, C.S., S.X. and S.Z.; funding acquisition, S.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Director Foundation (2019-ZSY) of the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences.  
Not applicable.  
The data presented in this work are available in Supplementary Materials.  
The authors declare no conflicts of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} PNPs & Polymeric Nanoparticles \\ H-bond & Hydrogen Bonding \\ CMYK & Cyan Magenta Yellow Key \\ PU & Polyurethane \\ PAA & Polyacrylic Acid \\ PVA & Polyvinyl Alcohol \\ CPT & Controlled Polymerization Technology \\ \end{tabular}