PC2, 0.1663PCA all sensors
4.4 Results
4.4.3 Ellipsometry
All films displayed responses to saturated hexane vapor. Pure films, however, displayed apparent thickness changes of 4–6 ˚A, similar to the nominal thickness change indicated by the change in signal displayed by a blank silicon sample wafer upon exposure to analyte.
Film deposition volumes were generally equal, but not rigorously controlled. However,
Mixed acid/plasticizer films swelled in the range of 4–8%, for overall shifts of 20–35 A. Pure plasticizer films swelled˚ ∼20% of their original thickness, a change of 30–40 ˚A.
Film baselines were stable, shifting ≤2% of their total value over all exposures, in most cases.
Oxalic acid films were thinner than all other films, and oxalic acid/plasticizer films displayed larger percent changes than did the other mixed films, although absolute changes were similar. Pure decanoic acid and decanoic acid/plasticizer films cast via spin coater were too unstable to perform ellipsometry measurements.
−1 0 1
−1 0 1
−5 0
5 CHCl
3
−2 0 2
−2 0 2
−2 0 2
time
−6 0 6
EtOAc
−5 0 5
−4 0 4
−4
−3 0 3
−6 0
6 hexane
−3 0 3
∆R/Rb x 1000
Day 13 Day 6 Day 3 Day 1
Figure 4.2: Single sensor responses of oxalic acid 75 CB to hexane, chloroform, and ethyl acetate on day 1, 3, 6 and 13 after creation. Day 1 exposure is for 100 s, all others are for 200 s. All exposures are atP/P0 = 0.01, in a total 2.5 L min−1 flow of air.
0 100 200 300 400
−1 0 1 2 3 4
time (s)
∆R/R b * 1000
0 100 200 300 400
−2 0 2 4 6
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3 4
time (s)
∆R/R b * 1000
CHCl3
0 100 200 300 400
−1 0 1 2 3
time (s)
∆R/R b * 1000
EtOAc C2
C4 C6 C8 C10 C12 C14
(a) (b)
(c) (d)
Figure 4.3: ∆R/Rb values of 200 second single exposures of dicarboxylic acid 75 CB to a) hexane, b) toluene, c) CHCl3, and d) ethyl acetate. Each analyte was presented at P/P0 = 0.01, in a total 2.5 L min−1flow of air.
0 100 200 300 400
0 2 4 0 2 4
hexane
time (s)
∆R/R b * 1000
0 100 200 300 400
−2 0 2 4 6
toluene
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3
CHCl3
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3
EtOAc
time (s)
∆R/R b * 1000 C2 C4 C6 C8 C10 C12 C14 (c)
(a) (b)
(d)
Figure 4.4: ∆R/Rb values of 200 second single exposures of dicarboxylic acid 40 CB to a) hexane, b) toluene, c) CHCl3 ,and d) ethyl acetate. Each analyte was presented at P/P0 = 0.01, in a total 2.5 L min−1flow of air.
0 100 200 300 400
−1 0 1 2 3
time (s)
∆R/R b * 1000
hexane
0 100 200 300 400
−1 0 1 3 5
toluene
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3 4
CHCl3
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2
3 EtOAc
time (s)
∆R/R b * 1000 C2 C4 C6 C8 C10 C12 C14 (a)
(c) (d)
(b)
Figure 4.5: ∆R/Rb values of 200 second single exposures of dicarboxylic acid 40/p to a) hexane, b) toluene, c) CHCl3, and d) ethyl acetate. Each analyte was presented atP/P0 = 0.01, in a total 2.5 L min−1flow of air.
0 100 200 300 400
−1 0 1 3 5
time (s)
∆R/R b * 1000
C14 C16 C18 C24
0 100 200 300 400
−1 0 2 4 6
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3 4
time (s)
∆R/R b * 1000
CHCl3
0 100 200 300 400
−1 0 1 2 3
time (s)
∆R/R b * 1000
EtOAc (c)
(a) (b)
(d)
Figure 4.6: ∆R/Rb values of 200 second single exposures of carboxylic acid 75 CB to a) hexane, b) toluene, c) CHCl3, and d) ethyl acetate. Each analyte was presented atP/P0 = 0.01, in a total 2.5 L min−1flow of air.
0 100 200 300 400
−2 0 2 4 6
hexane
time (s)
∆R/R b * 1000
0 100 200 300 400
−2 0 2 4 6
toluene
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3
4 CHCl
3
time (s)
∆R/R b * 1000
0 100 200 300 400
−1 0 1 2 3
EtOAc
time (s)
∆R/R b * 1000 C10 C14 C16 C18 C24
(b) (a)
(c) (d)
Figure 4.7: ∆R/Rb values of 200 second single exposures of carboxylic acid 40 CB to a) hexane, b) toluene, c) CHCl3, and d) ethyl acetate. Each analyte was presented atP/P0 = 0.01, in a total 2.5 L min−1flow of air.
0 100 200 300 400 1
0 1 3 5
time (s)
∆R/R b * 1000
hexane
0 100 200 300 400
−1 0 1 3 5
time (s)
∆R/R b * 1000
toluene
0 100 200 300 400
−1 0 1 2 3 4
time (s)
∆R/R b * 1000
CHCl3
0 100 200 300 400
−1 0 1 2 3
time (s)
∆R/R b * 1000
EtOAc C10
C14 C16 C18 C24
(a) (b)
(c) (d)
Figure 4.8: ∆R/Rb values of 200 second single exposures of carboxylic acid 40/p to a) hexane, b) toluene, c) CHCl3, and d) ethyl acetate. Each analyte was presented atP/P0 = 0.01, in a total 2.5 L min−1flow of air.
−5
0
5
10
15
−5 0
5 10
−4
−2 0 2 4
PC1, 0.58231 PC2, 0.29598
PCA, Dicarboxylic 75 CB
PC3, 0.044798
CHCl3
EtOH toluene EtOAc iPrOH heptane
Figure 4.9: PCA plot of dicarboxylic acid 75 CB sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
−10
−5
0
5
10 −5 0
5 10
−4
−2 0 2 4
PC2, 0.18117 PCA , Dicarboxylic 40 CB
PC1, 0.72692
PC3, 0.029921
hexane CHCl3
EtOH toluene EtOAc iPrOH heptane
Figure 4.10: PCA plot of dicarboxylic acid 40 CB sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
−10
−5
0
5
10 −4
−2 0
2 4
−5 0 5
PC2, 0.073045 PC1, 0.56029
PCA , Dicarboxylic 40CB/Plas
PC3, 0.065756
hexane CHCl3
EtOH toluene EtOAc iPrOH heptane
Figure 4.11: PCA plot of dicarboxylic acid 40/p sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
−5 0
5 10
−4
−2 0
2 4
−4
−2 0 2 4
PC1, 0.66261 PC2, 0.18918
PCA , Carboxylic 75 CB
PC3, 0.044713
CHCl3
EtOH toluene EtOAc iPrOH heptane
Figure 4.12: PCA plot of carboxylic acid 75 CB sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
−10
−5
0
5
10 −4 −3 −2 −1 0 1 2 3
−2 0 2
PC2, 0.077023 PCA , Carboxylic 40 CB
PC1, 0.74476
PC3, 0.049625
hexane CHCl3 EtOH toluene EtOAc iPrOH heptane
Figure 4.13: PCA plot of carboxylic acid 40 CB sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
−8
−6
−4
−2 0
2 4
6 −3 −2 −1 0 1 2 3
−5 0 5
PC2, 0.071724 PCA, Carboxylic 40 CB / Plas
PC1, 0.71567
PC3, 0.045353
hexane CHCl3
EtOH toluene EtOAc iPrOH heptane
Figure 4.14: PCA plot of carboxylic acid 40/p sensors. There are 25 exposures to each analyte. Numbers next to each principal component axis reflect the percentage of the total sensor response variance contained in that principal component
Dicarb.acidhexaneheptanetoluenechloroformEtOHiPrOHEtOAc
C20.52±0.300.59±0.281.59±0.270.09±0.221.69±0.172.00±0.192.86±0.22C42.32±0.033.11±0.314.00±0.272.02±0.131.50±0.211.85±0.172.22±0.24C62.36±0.303.12±0.264.27±0.262.14±0.141.67±0.232.06±0.182.46±0.26C81.87±0.242.28±0.213.73±0.232.66±0.111.67±0.191.91±0.162.45±0.16C101.71±0.202.01±0.183.36±0.192.39±0.101.36±0.151.62±0.121.97±0.12C121.59±0.231.91±0.243.30±0.282.34±0.121.40±0.181.65±0.152.04±0.18C141.49±0.211.81±0.233.20±0.271.79±0.131.36±0.171.62±0.141.96±0.17
C21.80±0.252.47±0.203.67±0.261.10±0.251.13±0.251.24±0.101.65±0.15C43.56±0.204.74±0.314.36±0.201.42±0.110.73±0.160.80±0.101.04±0.14C62.12±0.102.75±0.113.86±0.091.96±0.081.12±0.121.18±0.081.49±0.10C80.94±0.071.09±0.062.17±0.071.55±0.040.79±0.070.79±0.071.04±0.08C101.22±0.081.46±0.082.84±0.081.85±0.060.91±0.100.93±0.071.22±0.08C120.90±0.051.02±0.061.98±0.061.69±0.040.78±0.080.79±0.061.01±0.06C140.64±0.050.69±0.061.43±0.051.50±0.090.71±0.060.72±0.060.90±0.06
C22.42±0.202.78±0.223.48±0.213.21±0.191.11±0.211.03±0.151.49±0.18C42.37±0.272.93±0.303.44±0.292.28±0.251.20±0.271.24±0.211.69±0.23C61.78±0.222.02±0.252.69±0.232.75±0.220.99±0.170.93±0.151.30±0.21C81.23±0.161.28±0.191.90±0.172.25±0.190.87±0.170.69±0.141.13±0.16C101.01±0.210.92±0.271.72±0.252.97±0.270.98±0.210.74±0.201.21±0.24C121.17±0.231.19±0.271.73±0.232.58±0.270.89±0.210.71±0.201.11±0.26C140.99±0.150.95±0.161.53±0.152.55±0.220.81±0.140.75±0.141.05±0.15
4.3:∆Rmax/Rbvaluesx1,000foralldicarboxylicacidsmeasuredinthisstudy.Dataaremeansobtainedfrom25exposurestoaanalyte.Thereportederrorisonestandarddeviation.
CB%Dicarb.acidhexaneheptanetoluenechloroformEtOHiPrOHEtOAc 75C217±1223±1735±241±1348±2962±5468±53 C460±2883±41100±6348±3544±2852±2062±37 C659±2282±35148±8074±4758±2882±5972±41 C893±3892±47160±49257±10672±29131±14481±22 C1083±37102±44122±56128±6257±2071±2968±22 C1277±3498±46215±282220±17362±31105±81113±219 C1458±3175±38169±13691±5358±4281±5762±18 40C263±3086±49112±4522±1735±1840±1559±28 C4110±65132±5291±4750±3024±1834±1339±19 C6140±49177±93212±85155±9050±13104±9185±34 C850±3247±1698±2574±2441±1449±2051±24 C1089±8296±37133±78121±5159±2868±4267±23 C1251±1962±36118±9484±3053±3041±1947±15 C1436±1147±1877±2576±3554±2555±2658±27 40/pC2118±35146±88161±51163±6454±2655±2076±21 C427±936±1445±4028±1315±818±620±10 C621±822±726±1227±1015±912±816±10 C839±1739±1959±2478±3330±1425±1433±15 C1018±1615±825±1147±3715±411±517±5 C129±49±513±423±108±35±210±6 C1428±1336±1552±2998±6534±1824±1331±9 Table4.4:SNRforalldicarboxylicacidsmeasuredinthisstudy.Dataaremeansobtainedfrom25exposurestoagivenanalyte.The reportederrorisonestandarddeviation.
Carb.acidhexaneheptanetoluenechloroformEtOHiPrOHEtOAc
75C103.42±0.224.49±0.235.25±0.181.76±0.241.67±0.291.76±0.202.29±0.14C142.46±0.163.06±0.154.19±0.112.65±0.180.89±0.220.95±0.141.18±0.11C162.36±0.203.12±0.223.98±0.251.90±0.221.06±0.241.12±0.181.35±0.14C181.99±0.222.66±0.253.69±0.211.36±0.271.35±0.281.44±0.241.72±0.18C241.88±0.182.60±0.253.43±0.221.20±0.250.90±0.210.99±0.171.16±0.15
40C104.07±0.235.11±0.195.46±0.202.29±0.231.19±0.262.14±0.162.55±0.18C140.66±0.120.68±0.091.34±0.080.96±0.070.44±0.110.37±0.090.55±0.08C160.52±0.080.57±0.061.17±0.050.82±0.060.39±0.090.31±0.070.47±0.07C180.62±0.070.66±0.071.42±0.050.91±0.040.44±0.070.38±0.060.52±0.06C240.89±0.100.97±0.092.01±0.071.34±0.080.56±0.110.53±0.090.69±0.08
C103.50±0.324.53±0.304.81±0.353.31±0.301.07±0.161.11±0.211.40±0.16C140.77±0.120.79±0.081.35±0.111.37±0.130.50±0.070.40±0.100.58±0.08C160.77±0.090.79±0.071.43±0.091.37±0.090.46±0.050.37±0.070.53±0.06C180.87±0.090.90±0.071.51±0.101.63±0.090.45±0.080.38±0.070.54±0.08C240.85±0.120.93±0.121.41±0.111.43±0.130.42±0.080.39±0.110.51±0.07
4.5:∆Rmax/Rbvaluesx1,000forallcarboxylicacidsmeasuredinthisstudy.Dataaremeansobtainedfrom25exposurestoaanalyte.Thereportederrorisonestandarddeviation.
CB%Carb.acidhexaneheptanetoluenechloroformEtOHiPrOHEtOAc 75C10275±116421±337645±562128±5693±39146±77109±34 C14125±44187±130206±83165±10755±2866±3876±31 C1636±1745±2062±2129±1121±1122±926±19 C18181±149144±110292±31865±4669±2989±46108±115 C2462±3286±56104±4531±2233±1935±2240±23 40C10137±74126±41157±7152±2452±1666±3070±29 C1419±818±1238±1226±1215±1011±717±8 C1621±1220±644±2233±2117±913±616±7 C1850±1751±20133±6981±3939±2434±1452±29 C2428±1634±1662±4142±1719±818±921±8 40/pC10508±286841±629651±350495±374116±73162±78135±98 C1420±921±740±1535±1416±713±617±7 C1637±1737±1470±3073±3324±819±819±7 C1831±1336±2155±3251±1817±520±1119±7 C2456±13729±1542±1743±2115±614±619±8 Table4.6:SNRforallcarboxylicacidsmeasuredinthisstudy.Dataaremeansobtainedfrom25exposurestoagivenanalyte.The reportederrorisonestandarddeviation.
Figure 4.15: ∆ma/mf QCM values for all CB-containing films. Values are from the final run of each film, and are the average of 10 exposures to each analyte. Error is one standard deviation.
Figure 4.16: ∆ma/mf QCM values for all non-CB-containing films. Values are from the final run of each film, and are the average of 10 exposures to each analyte. Error is one standard deviation.
Acid Compound No DOP Plasticizer With Plasticizer t ( ˚A) ∆h/h(%) ∆h( ˚A) t ( ˚A) ∆h/h(%) ∆h( ˚A)
decanoic - - - -
myristic 361 2.4(0.7) 8.2(1.5) 388 5.5(0.3) 21.3(1.3)
315 1.3(0.4) 4.0(1.2) 456 6.0(0.7) 27.5(3.4)
stearic 262 1.8(0.1) 5.3(1.1) 501 4.2(0.5) 21.0(2.8)
252 2.0(0.4) 5.1(1.2) 295 8.1(0.3) 24.0(1.0)
palmitic 370 1.6(0.4) 6.0(1.6) 398 5.2(0.4) 19.8(1.5)
311 1.4(0.1) 4.2(0.4) 474 7.4(0.3) 35.4(1.3) tetracosanoic 275 2.4(0.4) 6.4(1.4) 440 8.1(0.3) 36.6(1.2) 340 1.3(0.2) 4.3(0.6) 413 6.5(0.5) 30.3(2.0)
oxalic 204 1.7(0.3) 3.6(0.7) 208 16.9(1.9) 34.5(3.8)
261 2.2(0.7) 5.7(2.0) 172 14.1(1.1) 23.7(1.5)
succinic 341 1.2(0.2) 3.9(0.6) 272 7.0(0.5) 18.9(1.4)
204 4.2(0.2) 8.6(0.3) 383 9.2(0.3) 35.3(1.1)
adipic 330 1.7(0.2) 5.6(0.8) 456 5.6(0.2) 25.4(1.2)
226 3.0(0.6) 7.5(0.3) 527 6.3(0.2) 33.1(1.3)
suberic 298 1.5(0.2) 4.4(0.6) 483 4.7(0.3) 22.7(1.5)
337 1.6(0.1) 5.2(0.3) 504 6.1(0.4) 30.8(2.3)
sebacic 327 1.3(0.1) 4.1(0.4) 510 4.6(0.3) 23.3(1.8)
387 1.3(0.2) 5.2(0.4) 553 4.0(0.3) 22.2(1.9) dodecanedioic 334 1.4(0.2) 4.6(0.8) 426 6.1(0.6) 26.2(2.7) 349 2.0(0.2) 6.9(0.6) 586 4.7(0.1) 27.6(0.9) tetradecanedioic 332 0.7(0.1) 2.5(0.3) 465 5.7(0.3) 26.3(1.3) 322 1.1(0.0) 3.6(0.1) 445 5.5(0.4) 25.5(2.1)
blank 5.1(0.4)
4.4(0.1)
plasticizer 167 19.1(0.9) 31.7(1.6)
162 23.4(0.6) 38.6(1.6) Table 4.7: Averaged ellipsometry responses of carboxylic and dicarboxylic acid films. Re- ported error is one standard deviation. Decanoic acid films deposited by spin coating were not stable.