Tuning Surface Properties of Poly(methyl methacrylate) Film Using Poly(perfluoromethyl methacrylate)s with Short Perfluorinated Side Chains

To control the surface properties of a commonly used polymer, poly­(methyl methacrylate) (PMMA), poly­(perfluoromethyl methacrylate)­s (PFMMAs) with short perfluorinated side groups (i.e., −CF₃, −CF₂CF₃, −(CF₃)₂, −CF₂CF₂CF₃) were used as blend components because of their good solubility in organic solvents, low surface energies, and high optical transmittance. The surface energies of the blend films of PFMMA with the −CF₃ group and PMMA increased continuously with increasing PMMA contents from 17.6 to 26.0 mN/m, whereas those of the other polymer blend films remained at very low levels (10.2–12.6 mN/m), similar to those of pure PFMMAs, even when the blends contained 90 wt %PMMA. Surface morphology and composition measurements revealed that this result originated from the different blend structures, such as lateral and vertical phase separations. We expect that these PFMMAs will be useful in widening the applicable window of PMMA

Search strategy using bORNs or measurements of concentration.

<p>(A) Search strategy based on a pair of sensors. The searcher compares measurements of the time since the last odor arrival, Δ, or measurements of concentration, <i>C</i>, registered by left and right sensors and steers in the direction of the shorter time or higher concentration. (B) Example trajectory of bORN-based strategy (initial position is x = 150 cm, y = 0 cm). The searcher begins at the “start” point and stops at the “end” point. The trajectory is continuous, with decisions made at every dot. Points that end outside the plume indicate that the searcher backtracks to its previous position. (C, D) Mean and standard error for number of steps required for strategies based on measurements of concentration (blue) and time since last encounter (bORN strategy, red) as a function of starting location relative to the source.</p

Encoding and decoding time since the last odor encounter from a population of bORNs (experimental data from the spiny lobster <i>Panulirus argus</i>).

<p>(A) Electrophysiological recordings of spontaneous bursting from three bORNs with different intrinsic burst frequencies (left), and bursting pattern of a single bORN (right) stimulated with odor (blue marks). Trials aligned in order of increasing time since last burst (bottom to top). Note that bORN does not respond to stimulus when time since last burst is short (bottom 4 trials) and instead, continues to burst spontaneously, (B) Probability of bursting in response to odorant as a function of time since last burst <i>τ</i>. Blue points are electrophysiologial data; blue line is sigmoid fit to data. Red curve represents the probability that the bORN will go <i>τ</i> seconds before bursting spontaneously (1—CDF of spontaneous inter-burst interval). Together, these curves tune the bORN to be most sensitive to odors that arrive with a particular frequency. (C) Probability of bursting in response to a stimulus as a function of stimulus frequency for two bORNs tuned by different evoked and spontaneous burst functions. (D) Raster plot (upper) and burst histogram (lower) of a heterogeneous population of 210 bORNs constructed from multiple single-neuron electrophysiological recordings showing spontaneous bursting and responses to odor stimuli (blue marks). This reconstructed population of bORNs encodes time between two odor stimuli (20.7 s). (E) The time interval between odor stimuli can be decoded from the bursting pattern of a heterogeneous bORN population shown in (D) using a simple maximum likelihood procedure (decoded interval is 23.2 s). Data are from [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004682#pcbi.1004682.ref019" target="_blank">19</a>].</p

Odor plume PLIF videos taken at 15 locations.

<p>Instantaneous odor concentration (expressed as % of source concentration) at (A) x = 50 cm, (B) x = 100 cm, (C) x = 150 cm, (D) x = 200 cm, (E) x = 250 cm from the source along the odor plume centerline, and (F) y = 5 cm, (G) y = 10 cm from the odor plume centerline at x = 150 cm.</p

Recurrence plots (upper panels) and corresponding concentration time series (lower panels) for selected locations in the plume: (A) x = 50 cm, (B) x = 150 cm from the source along the plume centerline, and (C) y = 10 cm from the centerline at x = 150 cm, where height is 2.5 cm from the substratum.

<p>Black points in the recurrence plots indicate that recurrence occurs; white regions indicate that recurrence does not occur (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004682#sec002" target="_blank">Results</a>).</p

Recurrence time and position in the plume.

<p>(A) Example trajectory in reconstructed phase space. Two types of recurrence time index are obtained by averaging time intervals between all successive recurrent points () or only returning points () in a circle of radius <i>r</i> centered at a reference point <b>x</b>₀. To estimate , the refractory period of at least some bORNs in the population would need to be short relative to the times between successive recurrence points. can be estimated with longer refractory periods. (B) Mean (points) and standard deviation of and indices for positions in downstream direction. (C) Mean and standard deviation of and indices for positions in cross-stream direction.</p