Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces - extrusion and characterisation of filaments for improved 3D-printed surfaces

At a Glance

Metadata	Details
Publication Date	2023-08-28
Journal	Microchimica Acta
Authors	Mateusz Cieślik, Agnieszka Susik, Mariusz Banasiak, Robert Bogdanowicz, Krzysztof Formela
Institutions	Gdańsk University of Technology, University of Gdańsk
Citations	18
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond Nanocarbon Composites for Electroanalysis

Executive Summary

This research successfully demonstrates the fabrication of the first conductive, 3D-printable Poly(lactic acid) (PLA) filaments incorporating diamondised nanocarbons (DNCs) for high-performance electroanalytical applications.

Core Achievement: Development of PLA composites loaded with Carbon Black (CB) for bulk conductivity and Detonation Nanodiamonds (DNDs) or Microwave Plasma Assisted Chemical Vapor Deposition (MPACVD) grown Boron-Doped Carbon Nanowalls (BCNWs) for enhanced electrocatalysis.
Performance Metric: The DNC-loaded electrodes significantly enhanced redox kinetics, reducing activation overpotentials compared to standard CB-PLA.
Analytical Sensitivity: Achieved a low Limit of Detection (LOD) for dopamine detection, reaching 0.12 µM using the CB20_BCNW5 composite, a 4-fold improvement over the reference CB-PLA (0.48 µM).
Material Insight: The study confirms that low concentrations (up to 5 wt%) of DNCs are sufficient to enhance electrocatalytic performance by ensuring uniform distribution and linear diffusion within the electrode surface.
6CCVD Relevance: The successful use of MPACVD-grown, heavily boron-doped carbon structures (BCNWs) directly validates 6CCVD’s core expertise in high-quality MPCVD diamond synthesis and doping control for advanced electrochemical sensors.

Technical Specifications

The following hard data points were extracted from the research, highlighting the material performance and synthesis parameters:

Parameter	Value	Unit	Context
Dopamine LOD (BCNW)	0.12	µM	Best performance achieved (CB20_BCNW5)
Dopamine LOD (DND)	0.18	µM	CB20_DND5 composite
Reference LOD (CB-PLA)	0.48	µM	CB20 composite
Redox Peak Separation (ΔE) (BCNW)	170	mV	For [Fe(CN)₆]^3-/4-, indicating high reversibility
Redox Peak Separation (ΔE) (DND)	192	mV	For [Fe(CN)₆]^3-/4-
Charge Transfer Resistance (R_CT) (BCNW)	~30	Ω	Lowest resistance achieved (CB20_BCNW5)
Optimal CB Concentration	20	wt%	Used in all DNC composites (CB20 base)
DNC Concentration	5	wt%	Maximum DNC loading tested
BCNW Growth Temperature	850	°C	MPACVD stage temperature
BCNW Boron Doping Ratio	2000	ppm	[B]/[C] ratio used during MPACVD
DND Crystallite Size	4.4	nm	Calculated via Scherrer formula

Key Methodologies

The experiment involved specialized synthesis of the diamondised nanocarbon filler (BCNWs) followed by composite fabrication and 3D printing.

BCNW Synthesis (MPACVD):
- Substrate: Micron-sized Glassy Carbon (GC) powder (SIGRADUR® G).
- System: Microwave Plasma Assisted Chemical Vapour Deposition (MPACVD) system (SEKI Technotron AX5400S).
- Conditions: Stage heated to 850 °C, Microwave Power set to 1300 W, Pressure at 50 Torr.
- Gas Mixture: H₂, CH₄, B₂H₆, and N₂.
- Doping: B₂H₆ used as boron dopant, set to 2000 ppm [B]/[C] ratio.
Composite Preparation:
- Matrix: Poly(lactic acid) (PLA) Ingeo Biopolymer 3D450.
- Fillers: Ensaco 250G Carbon Black (CB) and DNCs (DND or BCNW).
- Method: Melt-compounding using a laboratory conical twin screw extruder (2T30-16).
- Mixing Parameters: Circulation in bypass mode for 8 min, screw rotation speed 100 rpm.
Filament Extrusion:
- Extruder Barrel Temperatures: 140, 170, and 200 °C (hopper to die).
- Die Diameter: 1.75 mm.
Electrode Fabrication:
- Printing Method: Material Extrusion (ME) using a 3D Pen PRO printer.
- Printing Temperature: 230 °C.
- Electrode Surface Area: 0.4 cm².
Electrochemical Evaluation:
- Techniques: Cyclic Voltammetry (CV), Differential Pulse Voltammetry (DPV), and Electrochemical Impedance Spectroscopy (EIS).
- Target Analytes: Potassium ferrocyanides ([Fe(CN)₆]^3-/4-) for kinetics assessment and Dopamine for sensing application.

6CCVD Solutions & Capabilities

This research highlights the critical role of highly structured, boron-doped diamond materials in achieving superior electrocatalytic performance in additive manufacturing. 6CCVD is uniquely positioned to supply and customize the advanced diamond materials required to replicate, scale, and extend this groundbreaking work.

Applicable Materials for Enhanced Electroanalysis

The BCNWs used in this study are highly characteristic carbon structures rich in both sp² and sp³ phases, heavily doped with boron, and grown via MPCVD—6CCVD’s core expertise. To achieve or surpass the reported 0.12 µM LOD, 6CCVD recommends the following materials:

6CCVD Material	Description & Relevance to Research	Customization Potential
Heavy Boron-Doped PCD	High-conductivity, large-area Polycrystalline Diamond (PCD) wafers. Ideal for processing into high-purity, conductive nanofillers/powders superior to the GC-supported BCNWs used.	Wafers up to 125mm diameter. Thicknesses from 0.1 µm to 500 µm.
Boron-Doped Diamond (BDD) Substrates	High-quality, highly conductive BDD films grown directly via MPCVD, offering the wide electrolytic window and low charge transfer resistance cited as unique BDD properties.	Substrates up to 10mm thick. Custom doping levels (heavy B-doping for maximum conductivity).
Single Crystal Diamond (SCD)	For applications requiring ultimate purity and controlled surface termination (e.g., for specific functionalization or surface activation studies).	Polishing available to Ra < 1nm. Custom dimensions and orientations.

Customization Potential for 3D-Printed Electrodes

The fabrication of 3D-printed electrodes requires precise material handling and integration. 6CCVD offers specialized services to streamline the development of next-generation electroanalytical platforms:

Custom Nanofiller Preparation: We can supply high-purity, heavily boron-doped diamond (BDD) material in various forms (wafers, plates, or processed powders) optimized for compounding into conductive filaments, ensuring superior sp³ content and doping control compared to detonation nanodiamonds.
Advanced Metalization Services: The paper utilized a copper plate/wire for electrical contact. 6CCVD offers in-house metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for creating robust, low-resistance contacts directly onto diamond substrates or composite structures, crucial for reliable sensor integration.
Precision Machining: We provide custom laser cutting and shaping services for both SCD and PCD plates, allowing researchers to design and test complex electrode geometries that integrate seamlessly with 3D-printed bodies.

Engineering Support

The successful integration of DNCs into the PLA matrix is highly dependent on achieving a balance between rheology, thermal stability, and electrical percolation. 6CCVD’s in-house PhD material science team specializes in MPCVD growth parameters and diamond surface chemistry.

Material Selection Consultation: Our experts can assist researchers in selecting the optimal diamond material (SCD, PCD, or BDD) and appropriate surface termination to maximize matrix-filler interactions and enhance the electrocatalytic performance for similar Dopamine Detection or general electroanalytical projects.
Global Supply Chain: We offer reliable global shipping (DDU default, DDP available) to ensure rapid delivery of custom diamond materials worldwide, supporting time-sensitive research and development cycles.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

Tech Support

Original Source

DOI: https://doi.org/10.1007/s00604-023-05940-7