Semiconductive Materials with Tunable Electrical Resistance and Surface Polarity Obtained by Asymmetric Functionalization of Janus Nanoparticles

Abstract

Janus nanoparticles (JNPs) can offer significant potential for synthesis of multifunctional materials, due to their inherent property contrast between the lobes. Asymmetric surface chemical modifications on JNPs can be performed such that each lobe can carry different surface and/or bulk‐like properties, which could be combined in surprising ways. In this work, it is shown that snowman‐type polymeric JNPs can be used to make conductive materials with tunable resistance and surface polarity. By changing the relative size between a conductive and an electrically insulating lobe, the bulk powder conductivity within a series of JNPs by a factor of 10 without changing the intrinsic conductivity of the polymer can be tuned. In the same time, the surface polarity of the powder material decreased by a factor of 5. The possibility to synthesize multifunctional materials from JNPs building blocks that enable the coupling of a bulk‐like property with a surface functionality is therefore demonstrated.

Amphiphilic Janus Particles at Interfaces

“…These properties can be bulk-like properties or surface properties. For example, one can combine electric, magnetic and optic properties on each Janus lobes in addition to amphiphilicity, a surface property [6]. By doing this one can couple surface and bulk properties and combine them in surprising new ways.…”

“…However, it would be more useful if amphiphilicity can be discussed quantitatively and can be measured. In a different approach to quantify the amphiphilicity of any shape of JPs Honciuc et al [1,6,42] have proposed the direct calculation of the HLB balance of a JP using Griffin's approach [43], that is, the same model used to calculate the HLB balance for a homologous series of surfactants [40] and adapted it for JPs:…”

“…In practice, to determine F one must know the surface energy and its polar and dispersive components which is not trivial. Recently, Mihali and Honciuc [6] have measured the surface energy and the polar/disperse components of each Janus lobes in a homologous series of semiconducting PPy/P(3-TSPM) JPs with increasing size of the polar lobe and with these values they have calculated the corresponding weighting factors F and subsequently the HLB values, these are given in Table 4.1. Fig.…”

“…JPs can be multifunctional because they can carry different properties on each lobe; this is especially attractive to creating new multifunctional materials where the surface and bulk-like properties can be combined to obtain unexpected functionalities. For example, it has been demonstrated that conductivity and surface polarity of snowman-type JPs can be tuned by changing the lobe ratio between a semiconductive lobe and an electrically insulating lobe [6]. This opens up the path to new multifunctional materials made from Janus building block that carry on the different lobes different functionalities, optic, magnetic, surface functional groups, etc.…”

Polymeric Janus Nanoparticles: Recent Advances in Synthetic Strategies, Materials Properties, and Applications

“…Through these above‐mentioned methods, micro‐ or nanometer size Janus particles with different compositions and architectures have been synthesized. According to the composition, Janus particles can be divide into three categories: polymeric materials based soft system, inorganic materials based hard system, and polymer/inorganic materials based hybrid system . In recent years, polymeric Janus particles consisting of two incompatible sides of different chemistry and surface functions have received attracted increasing attention .…”