Nanodiamond-Coated PLA Electrodes for Stable Electrochemical Sensing

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Solution Overview

Problem

Existing electrodes for electrochemical measurements face issues of instability over time, biofouling in biological media, poor electrical conductivity, low mechanical stability, and the need for high temperatures and expensive, rigid deposition substrates.

Innovation Solution

A composite electrode composed of a conductive polylactic acid (PLA) fibre or graphene-doped PLA layer coated with a nanodiamond foil or powder, produced using 3D printing and microwave plasma-assisted chemical vapour deposition, with a graphene/PLA inner layer and a nanodiamond outer layer, enhancing electrical conductivity, mechanical stability, and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrodes are used for electrochemical measurements, then basic electrochemical function is achieved, but instability over time and biofouling in biological media occur

Engineering Contradiction:
Improvestability over timeVSAvoidbiofouling
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite structure combining conductive PLA fiber with nanodiamond powder coating. The nanodiamond coating layer (0.1-5 μm thickness) provides chemical inertness and resistance to biofouling, while the conductive PLA base provides electrical conductivity. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both stability and resistance to harmful biological effects.

Inventive Principle:
Principle #40Composite materials

2Reliability

If carbon black/PLA or graphene/PLA is used as input material for 3D-printed electrodes, then electrical conductivity is improved, but mechanical stability and flexibility deteriorate

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the concentration of conductive filler (carbon black or graphene) in the PLA matrix to find the optimal balance between electrical conductivity and mechanical properties. It also controls the nanodiamond coating thickness (0.1-5 μm) to enhance mechanical stability without compromising flexibility. By carefully adjusting these material parameters, the patent achieves both good electrical conductivity and mechanical stability simultaneously.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high temperature deposition methods are used for electrode manufacturing, then material properties are improved, but cost increases and flexible substrates cannot be used

Engineering Contradiction:
Improvematerial propertiesVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces traditional high-temperature physical vapor deposition methods with a solution-based coating approach using nanodiamond powder suspended in a binder solution. This allows deposition at room temperature or low temperatures, enabling the use of flexible and temperature-sensitive substrates while reducing manufacturing cost and energy consumption. The nanodiamond powder forms a stable coating without requiring high-temperature processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The composite electrode exhibits high electrical conductivity, mechanical stability, low cost, and flexibility, with a wide electrochemical potential window and resistance to aggressive chemicals, enabling efficient electrochemical measurements.

Implementation Method 1

produced using 3D printing and microwave plasma-assisted chemical vapour deposition

Methodology Applied
Scientific EffectMicrowave plasma-assisted chemical vapour deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 2

A method of producing diamond foils is known from the description of patent application ref. PL 425610 A. Thin diamond foils, also known as nanodiamond foils (NDF) are produced by microwave plasma-assisted chemical vapour deposition (MW PA CVD).

Methodology Applied
Scientific EffectChemical vapour deposition: Chemical Vapour Deposition

Data Source

PatentEP4242648B1Composite electrodes for electrochemical measurements
Publication Date: 2025.11.19 POLITECHNIKA GDANSKA
  • EP4242648B1 patent drawingFigure 1~2
  • EP4242648B1 patent drawingFigure 3

AI summary

Electrode for electrochemical measurements, made of two layers, with one layer made of conductive polylactic acid (PLA) fibre or conductive polylactic acid (PLA) fibre doped with graphene, being a graphene-polymer layer, in which the weight ratio of graphene to PLA was 0.5% to 20% of graphene by weight and 99.5% to 80% of PLA by weight in the same layer of the electrode, and the layer is coated with nanodiamond foil (NDF) or a layer of nanodiamond powder (NDP). The layer of PLA or graphene/PLA is 0.1 to 5 mm thick and is coated with a layer 50 nm to 1500 nm thick being up to 0.1% of the entire electrode weight.