Sliding on slide-ring gels
Data files
Sep 25, 2024 version files 2.38 MB
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2024_Rhode_TribLett_Dataset.zip
2.37 MB
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README.md
11.51 KB
Abstract
Recent investigations have pointed to physical entanglements that greatly outnumber chemical crosslinks as key sources of energy dissipation and low friction in hydrogel networks. Slide-ring gels are an emerging class of hydrogels described by their mobile crosslinks, which are formed by rings topologically constrained to slide along linear polymer chains within the network. These materials have enjoyed decades of study by polymer chemists but have been underexplored by the tribology community. In this work, we synthesized a pseudo-rotaxane crosslinker from poly(ethylene glycol) diacrylate (PEG-diacrylate) and α-cyclodextrin-acrylate followed by hydrogel networks by connecting the sliding crosslinks with polyacrylamide chains. The mechanical and tribological properties of slide-ring hydrogels were investigated using a custom-built microtribometer. Slide-ring hydrogels exhibit unique behavior compared to conventional covalently-crosslinked polyacrylamide hydrogels and offer a vast design space for future investigations.
README: Sliding on slide-ring gels
https://doi.org/10.5061/dryad.ksn02v7dv
Description of the data and file structure
Data from: Sliding on Slide-Ring Gels
Article DOI: 10.1007/s11249-024-01920-x
Authors:
Andrew R. Rhode, University of California, Santa Barbara
Iván Montes de Oca, Universidade da Coruña
Michael L. Chabinyc, University of California, Santa Barbara
Christopher M. Bates, University of California, Santa Barbara
Angela A. Pitenis, University of California, Santa Barbara, apitenis@ucsb.edu
Files and variables
File: 2024_Rhode_TribLett_Dataset.zip
File List
A) Table_1.csv
B) Fig_2a.csv
C) Fig_2b.csv
D) Fig_2c.csv
E) Fig_3a.csv
F) Fig_3b.csv
G) Fig_3c.csv
H) Fig_4a.csv
I) Fig_4b.csv
J) Fig_S1.csv
K) Fig_S2.csv
L) Table_S1.csv
L) Fig_S3.csv
A) Table_1.csv
Column 1: Concentration of acrylamide in the gel precursor solution in wt%
Column 2: Concentration of pseudo-rotaxane in the gel precursor solution in wt%
Column 3: Concentration of ammonium persulfate (APS) in the gel precursor solution in wt%
Column 4: Concentration of N,N,N',N'-Tetramethylethylenediamine (TEMED) in the gel precursor solution in wt%
Column 5: Concentration of water in the gel precursor solution in wt%
Figure 2: Indentation data
B) Fig_2a.csv
Column 1: position of probe in micrometers for a 1.0 wt% sample indent (x)
Column 2: Normal force in micronewtons for a 1.0 wt% sample indent (y)
Column 3: position of probe in micrometers for a 1.5 wt% sample indent (x)
Column 4: Normal force in micro newtons for a 1.5 wt% sample indent (y)
C) Fig_2b.csv
Column 1: position of probe in micrometers for a 1.0 wt% sample indent with a 10 minute hold at the maximum force (x)
Column 2: Normal force in micronewtons for a 1.0 wt% sample with a 10 minutes hold at the maximum force (y)
D) Fig_2c.csv
Column 1: Sample identifications
Column 2: Dwell time in seconds (x)
Column 3: average Work of adhesion in microjoules (y)
Column 4: Standard deviation of work of adhesion in microjoules (+/- y)
Rows 2-5: Data for 1.0 wt% cross linked sample 2
Rows 8-11: Data for 1.5 wt% cross linked sample 1
Figure 3: Friction data
E) Fig_3a.csv
Column 1: Lateral position of the probe in micrometers for the 10 micron per second loop (x)
Column 2: Friction force in micronewtons for the 10 micron per second loop (y)
Column 3: Lateral position of the probe in micrometers for the 100 micron per second loop (x)
Column 4: Friction force in micronewtons for the 100 micron per second loop (y)
Note: Raw data has been shifted to align with the region of 0 to 6000 micrometers. Figure 3a is plotted with the position in millimeters on the x axis for visual clarity. 1 millimeter is 1000 micrometers. The friction loops in Fig 3a come from 1.5 wt% sample 1
F) Fig_3b.csv
Column 1: Lateral position of the probe in micrometers for the 10 micron per second loop (x).
Column 2: Friction force in micronewtons for the 10 micron per second loop (y)
Column 3: Lateral position of the probe in micrometers for the 100 micron per second loop (x).
Column 4: Friction force in micronewtons for the 100 micron per second loop (y)
Note: Raw data has been shifted to align with the region of 0 to 6000 micrometers. Figure 3a is plotted with the position in millimeters on the x axis for visual clarity. 1 millimeter is 1000 micrometers. The friction loops in Fig 3a come from 1.0 wt% sample 2
G) Fig_3c.csv
Column 1: Sample identifier
Column 2: velocity in micrometers per second and force in micronewtons of the friction measurements
Column 3: Average Hertz reduced modulus determined from indentation measurements of 5 repeats on 3 sites of 2 samples
Column 4: Standard deviation of Hertz reduced modulus determined from indentation measurements of 5 repeats on 3 sites of 2 samples
Column 5: Sliding speed in micrometers per second (x)
Column 6: Measurement normal force in micronewtons
Column 7: Average friction coefficient across two measurements for each formulation and set of parameters (y)
Column 8: Standard deviation of friction coefficient across two measurements for each formulation and set of parameters (+/- y)
Column 9: Average friction force in micronewtons across two measurements for each formulation and set of parameters
Column 10: Standard deviation of friction force in micronewtons across two measurements for each formulation and set of parameters
Column 11: Average normal force in micronewtons across two measurements for each formulation and set of parameters
Column 12: Standard deviation of normal force in micronewtons across two measurements for each formulation and set of parameters
Note: Rows 2-6 correspond to measurements of 1.0 wt% cross linked gels. Rows 8-12 correspond to measurements of 1.5 wt% cross linked gels. Figure 3c plots only the average and standard deviation of friction coefficient (columns 7 and 8) against sliding speed (column 5) for measurements with normal force of 500 micronewtons (rows 2,3,4, 8,9,10)
Figure 4. Comparison of slide-ring and fixed cross linked hydrogels
H) Fig_4a.csv
Column 1: Sample name
Column 2: Average hertz reduced modulus in kilopascals across both samples of a given type (x)
Column 3: Standard deviation of hertz reduced modulus in kilopascals across both samples of a given type (+/- x)
Column 4: Sliding speed of friction measurements in micrometers per second
Column 5: Target normal force of friction measurements in micronewtons
Column 6: Average friction coefficient resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed (y)
Column 7: Standard deviation of friction coefficient resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed (+/- y)
Column 8: Average friction force resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed
Column 9: Standard deviation of friction force resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed
Column 10: Average normal force resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed
Column 11: Standard deviation of normal force resulting from sliding experiments on two samples of the same formulation with the same target normal force and sliding speed
Note: Only the data for sliding speed 100 micrometers per second and normal force 500 micronewtons are plotted in Figure 4a. This corresponds to Rows 2 and 8. The columns plotted are 2 (x), 3 (+/- x), 6 (y), and 7 (+/- y)
I) Fig_4b.csv
Column 1: Sample name
Column 2: Average Hertz reduced modulus in kilopascals
Column 3: Standard deviation of Hertz reduced modulus in kilopascals
Column 4: Sliding speed in micrometers per second
Column 5: Average normal force of sliding experiment in micronewtons
Column 6: Standard deviation of normal force of sliding experiment in micronewtons
Column 7: Average friction force of sliding experiment in micronewtons
Column 8: Standard deviation of friction force of sliding experiment in micronewtons
Column 9: Average friction coefficient of sliding experiment (y)
Column 10: Standard deviation of friction coefficient of sliding experiment (+/- y)
Column 11: Calculated fluid film thickness resulting from each sliding experiment in nanometers (y)
Note: The average and standard deviation of friction coefficient for 1.0wt% sample 1 (columns 9-10, row 15) are intentionally left blank, as this measurement resulted in a friction coefficient below the noise floor of the tribometer. Fig 4b plots column 9 (y) and 10 (+/- y) against column 11 (x)
J) Fig_S1.png: Image of pseudo-rotaxane solutions
The leftmost vial is pseudo-rotaxane solution. The middle vial is a solution of alpha-cyclodextrin-acrylate. The rightmost vial is pure DI water
K) Fig_S2.csv: NMR
Row 1 has sample identifications for internal use only
Column 1: Chemical shift (horizontal axis) in parts per million (ppm) (x)
Column 2: Intensity (arbitrary units) of signal for PEG-Diacrylate (y)
Column 3: Intensity (arbitrary units) of signal for alpha-cyclodextrin-acrylate (y)
Column 4: Intensity (arbitrary units) of signal for pseudo-rotaxane complex made from mixing PEG-Diacrylate and alpha-cyclodextrin-acrylate (y)
L) Table_S1.csv: Swelling measurements of slide-ring gels
Column 1: Sample name
Column 2: Ratio of final diameter to initial diameter
Column 3: Cubed ratio of final to initial diameter
M) Fig_S3
Column 1: Lateral position in micrometers (x)
Column 2: friction coefficient (y)
Note: The data has been shifted to align with the position range of 0 to 6000 micrometers and to align free sliding regime in the middle millimeter of the sliding path with the friction coefficient value of 0
N) Indents_Slidering.csv
Column 1: Names of cycles for internal use
Column 2: Radius of curvature of glass probe in millimeters
Column 3: Maximum force for hertz fit for determination of reduced modulus
Column 4: Hertz reduced modulus for one cycle
Column 5: Maximum adhesive force in a given cycle in micronewtons
Column 6: Maximum normal force in a given cycle in micronewtons
Column 7: Work of adhesion for a given cycle in microjoules
Table 1: Data for indents on 1.5 wt% Sample 1 (Rows 2-18)
Table 2: Data for indents on 1.5 wt% Sample 2 (Rows 21-37)
Table 3: Data for indents on 1.0 wt% Sample 1 (Rows 41-58)
Table 4: Data for indents on 1.0 wt% Sample 2 (Rows 60-76)
Note: At the end of each table, the average and standard deviation of the Hertz reduced modulus for the corresponding sample are calculated. The second to last row of each table is the average, and the last row is the standard deviation. All indentation measurements in this file use a constant speed of 10 micrometers per second
O) Indent_hold.csv
Column 1: Name of cycle for internal use
Column 2: Probe radius of curvature in millimeters
Column 3: The maximum normal force in micronewtons during a given adhesion measurement
Column 4: The maximum adhesive force in micronewtons during a given adhesion measurement
Column 5: The work of adhesion in microjoules for a given adhesion measurement
Table 1 (rows 3-16) have data for 1.5 wt% sample 1 with a dwell time of 0 seconds
Table 2 (rows 3-16) have data for 1.5 wt% sample 1 with a dwell time of 10 seconds
Table 3 (rows 3-16) have data for 1.5 wt% sample 1 with a dwell time of 60 seconds
Table 4 (rows 3-16) have data for 1.5 wt% sample 1 with a dwell time of 600 seconds
Table 5 (rows 3-16) have data for 1.0 wt% sample 2 with a dwell time of 0 seconds
Table 6 (rows 3-16) have data for 1.0 wt% sample 2 with a dwell time of 10 seconds
Table 7 (rows 3-16) have data for 1.0 wt% sample 2 with a dwell time of 60 seconds
Table 8 (rows 3-16) have data for 1.0 wt% sample 2 with a dwell time of 600 seconds
The second to last row in each table contains the average value for the maximum normal force, maximum adhesive force, and work of adhesion across all measurements of one sample with one dwell time
Note: All indentation measurements in this file used a target maximum force of 1000 micronewtons and had a constant indentation speed of 5 micrometers per second
Code/software
Matlab codes are provided ias .txt files.
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Methods
Microindentations and sliding experiments were conducted with a custom-built linear reciprocating tribometer. Data was analyzed and processed with the following Matlab codes Compiling_Friction_Data_v5 and Tribometer_Indent_Analysis_v3_Wad
NMR spectroscopy was conducted with a Varian VNMRS 600 MHz spectrometer using D2O as a solvent. In all cases, the number of scans was 32, and the relaxation time was 1 s. The data files were processed in MestReNova. Using MestReNova, NMR CSV files were generated for this repository.