Analysis of the anchoring-solvation dual mechanism of hyperdispersants in electronic pastes
Publish Time: 2025-07-14
As a key material in the manufacture of electronic components, the performance of electronic pastes directly affects the quality and reliability of the final product. However, due to the high surface energy and small particle size of solid particles in electronic pastes, they are very easy to agglomerate, resulting in uneven dispersion of the paste, which in turn affects the stability of processes such as printing and coating, as well as the electrical properties of the product. As a highly efficient dispersing aid, hyperdispersants have shown excellent dispersion effects in the field of electronic pastes by virtue of their unique anchoring-solvation dual mechanism. This article will deeply analyze the anchoring-solvation dual mechanism of hyperdispersants, and explore their application value in electronic pastes in combination with specific use cases.Anchoring-solvation dual mechanism of hyperdispersantsAnchoring mechanismThe molecular structure of hyperdispersants contains anchoring groups, which can strongly interact with the surface of solid particles, thereby firmly adsorbing on the surface of particles. According to the different polarity of the particle surface, the anchoring methods can be divided into the following types:Single-point anchoring: For inorganic particles with strong polar surfaces, such as titanium dioxide, iron oxide, etc., the hyperdispersant only needs a single anchoring group to combine with the strong polar groups on the particle surface in the form of ion pairs to form a stable single-point anchoring. This anchoring method can ensure that the hyperdispersant is firmly adsorbed on the particle surface and is not easy to desorb.Multi-point anchoring: For organic particles with weak polar surfaces, such as organic pigments and some inorganic pigments, hyperdispersants usually require multiple anchoring groups. These groups form multi-point anchoring on the particle surface through dipole forces, further enhancing the stability of adsorption. Multi-point anchoring can effectively prevent the particles from reaggregating in the dispersion medium and improve the long-term stability of the dispersion system.Synergistic anchoring: For completely non-polar or low-polarity organic pigments and some carbon blacks, the direct use of hyperdispersants is not effective due to the lack of active groups on the particle surface for hyperdispersant anchoring. At this time, a surface enhancer needs to be introduced. Surfactant is a pigment derivative with polar groups, and its molecular structure and physical and chemical properties are very similar to those of dispersed pigments. It can be tightly adsorbed on the surface of organic pigments through intermolecular van der Waals forces, and at the same time, the polar groups in its molecular structure provide chemical positions for the adsorption of hyperdispersant anchoring groups. Through this synergistic effect, hyperdispersants can have a very effective wetting and stabilizing effect on organic pigments.Solvation MechanismThe other part of the hyperdispersant is the solvated polymer chain, which has good compatibility in the dispersion medium, can adopt a relatively extended conformation, and form a protective layer of sufficient thickness on the surface of solid particles. The key to the solvation mechanism lies in the control of the length of the polymer chain:Moderate chain length: When the length of the polymer chain is too short, the stereo effect is not obvious, and it cannot produce enough steric hindrance to prevent the particles from approaching and agglomerating each other. When the polymer chain is too long, although it can provide greater steric hindrance, the too long chain will have too high affinity for the medium, resulting in the desorption of the hyperdispersant from the particle surface. In addition, overly long chains may also undergo reverse folding, compressing the steric hindrance of steric barriers or causing entanglement with adjacent molecules, ultimately inducing reaggregation or flocculation of particles. Therefore, the rational regulation of polymer chain length is crucial to ensure the dispersion effect of superdispersants.Environmental responsiveness: The solvated chains of some superdispersants are environmentally responsive, and their hydrodynamic diameters change with changes in pH and temperature. For example, comb copolymers in polyacrylate solutions can self-assemble to form spherical core-shell nanostructured particles, in which the hydrophobic PA backbone is the core, the PMAA block is the shell, and the PNIPAAm block is the crown. This micellization behavior is affected by the balance between electrostatic repulsion and PMAA hydrogen bonds, and can adjust its conformation according to changes in environmental conditions, thereby achieving dynamic stabilization of the dispersed system.Use cases of superdispersants in electronic pastesCase 1: Dispersion of carbon nanotube electronic pastesAs a nanomaterial with excellent electrical and mechanical properties, carbon nanotubes have broad application prospects in the field of electronic pastes. However, carbon nanotubes have high surface energy and porous structure, which makes it extremely difficult to disperse them in the liquid phase. In traditional dispersion methods, carbon nanotubes are often prone to agglomeration and cannot fully exert their performance advantages.In response to this problem, an electronic material company has developed a hyperdispersant based on polyether-modified styrene-maleic anhydride copolymer. The hyperdispersant forms a single-point anchor with the polar groups on the surface of carbon nanotubes through its anchoring group, and at the same time, its solvated polymer chain forms a protective layer of sufficient thickness in the dispersion medium, which effectively prevents the carbon nanotubes from approaching each other and agglomerating. The experimental results show that after using the hyperdispersant, the dispersion uniformity of the carbon nanotube electronic paste is significantly improved, and the agglomeration phenomenon is significantly reduced. During the printing process, the paste can smoothly pass through the screen to form a uniform film. In addition, the electronic components prepared by the paste also perform well in electrical properties, with significantly reduced resistivity and significantly improved conductivity.Case 2: Dispersion of ceramic electronic pasteCeramic electronic paste is a key material for manufacturing electronic components such as multilayer ceramic capacitors (MLCC). However, ceramic powders are prone to agglomeration due to their small particle size and large specific surface area, which leads to increased viscosity and poor fluidity of the slurry. This not only affects the stability of processes such as printing and coating, but also reduces the yield and performance of the product.A ceramic electronic slurry manufacturer uses a hyperdispersant based on polyacrylate solution to solve this problem. The hyperdispersant forms multi-point anchoring with polar groups such as hydroxyl groups on the surface of the ceramic powder through its anchoring group, and its solvated polymer chain forms a stable protective layer in the dispersion medium. The experimental results show that after using the hyperdispersant, the dispersibility of the ceramic electronic slurry is significantly improved and the agglomeration phenomenon is effectively controlled. The viscosity of the slurry is reduced and the fluidity is improved, making the printing, coating and other processes more stable and reliable. In addition, the MLCC products prepared by the slurry meet or exceed the industry standard requirements in terms of key performance indicators such as capacitance and loss, which improves the market competitiveness of the products.Case 3: Dispersion of conductive silver pasteConductive silver paste is a key material for manufacturing electronic products such as solar cells and touch screens. However, silver powder, as the main component of conductive silver paste, is very prone to agglomeration due to its high surface energy and small particle size. This not only affects the conductive properties of the silver paste, but also reduces the stability of processes such as printing and coating.A conductive silver paste manufacturer uses a hyperdispersant based on styrene-maleic anhydride copolymer to solve this problem. The hyperdispersant forms a single-point anchor with the polar groups on the surface of the silver powder through its anchoring group, and its solvated polymer chain forms a stable protective layer in the dispersion medium. The experimental results show that after using the hyperdispersant, the dispersibility of the conductive silver paste is significantly improved, and the agglomeration of silver powder is effectively controlled. The conductive properties of the paste are significantly improved, and the resistivity is reduced. In addition, the paste can form a uniform film during the printing process, which improves the product yield and performance stability.
