Electrochemistry of platinum nanoparticles supported in polypyrrole (PPy)/C composite materials

Stretchable conductive polypyrrole/polyurethane (PPy/PU) strain sensor with netlike microcracks for human breath detection

The development of wearable electronics that can monitor human physiological information demands specially structured materials with excellent stretchability and electrical conductivity. In this study, a new stretchable conductive polypyrrole/polyurethane (PPy/PU) elastomer was designed and prepared by surface diffusion and in situ polymerization of PPy inside and on porous PU substrates. The structures allowed the formation of netlike microcracks under stretching. The netlike microcrack structures make possible the reversible changes in the electrical resistance of PPy/PU elastomers under stretching and releasing cycles. The variations in morphology and chemical structures, stretchability, and conductivity as well as the sensitivity of resistance change under stretching cycles were investigated. The mechanism of reversible conductivity of the PPy/PU elastomer was proposed. This property was then used to construct a waistband-like human breath detector. The results demonstrated its potential as a strain sensor for human health care applications by showing reversible resistance changes in the repeated stretching and contracting motion when human breathes in and out.

One-pot formation of multifunctional Pt-conducting polymer intercalated nanostructures

A novel multifunctional Pt nanoparticle@PPy nanofiber intercalated structure (Pt NP@PPy NF) has been synthesized facilely in one-pot. Pt NPs, with size and facet control, were nicely assembled and embedded into the polymer nanofiber network. Polyvinylpyrrolidone (PVP) was used during the synthesis process which would assist the self-assembly of the metal nanoparticles and polymer backbones into the intercalated structure. Space-confined distribution of the Pt NPs was achieved within the large dimension PPy nanofiber network, which could enhance the interfacial electron transfer process as well as diminish the catalyst deformation. The as-formed Pt NPs have a cluster-like structure and are mainly composed of 3.5 nm primary Pt particles with (100) surface atoms. Enhanced electrocatalytic properties were shown by the Pt NP@PPy NF intercalated structure, with sufficiently high enzyme-less glucose biosensitivity and a long linear range from 1-30 mM (R = 0.9995). High electrochemical cycling stability, chloride (Cl(-)) tolerance and good selectivity are also obtained for the Pt NP@PPy NF structure, as the electrode showed no obvious response to the common interfering agents, such as ascorbic acid (AA), uric acid (UA), and 4-acetamidophenol (AP). Furthermore, the Pt NP@PPy NF showed excellent catalytic activity for the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR), which displayed sufficient CO tolerance, and higher activity compared to the commercial Pt/C catalyst. This intrinsically multifunctional Pt NP@PPy NF with well-controlled Pt facets thus could serve as an advanced electrocatalyst for biosensing and fuel cell applications, surpassing the performance of many existing materials.